Hi Everyone!

Welcome to version 0.50.12! It’s been about three months since the 0.50.11 Milestone release, and there’s a lot to cover.

First, a heads-up for those still on 0.50.11: after declaring it a Milestone, we discovered a nasty bug involving ECM and C3 interactions. That bug is fixed in this release. However, we don’t anticipate 0.50.12 achieving Milestone status. There are too many big-ticket items in MegaMek that will need time to settle and stabilize.

A Farewell to a Warrior

For those who haven’t been following, early in the new year Illiani left the projects. She was the primary MekHQ developer and a driving force behind MekHQ’s improvements over the last couple of years. As we announced on Discord:

It is with a heavy heart that I announce Illiani has departed the MegaMek project. Like Kerensky leading the Exodus Fleet beyond the Periphery, sometimes the most dedicated warriors reach a point where they must step away from the front lines. After years of tireless service, Illiani has made the difficult decision to leave. We wish her peace, rest, and fair winds wherever her JumpShip takes her next.

For those who don’t know the scope of what she accomplished: Illiani was a change agent in every sense of the word. She didn’t just contribute to MekHQ. She transformed it. Every system bears her fingerprints. Nearly 9,000 commits. The #1 contributor to the MekHQ codebase. The numbers alone don’t capture it. She elevated this program in ways that will benefit players for years to come.

I need the community to understand what this means going forward. Illiani was MekHQ’s primary developer. The pace of development, particularly major new features, will slow significantly for the foreseeable future. Our remaining developers will continue to address bugs and issues as they arise, but remember: this is a volunteer project, and developers work on what they choose to work on. The programs will continue. MekHQ will continue. But this is a significant loss.

On a personal note, I’m going to miss her. Her impact on this community was phenomenal. The door remains open should she ever choose to return.

BattleTech Core Rules: What’s Our Plan?

Catalyst has announced the new Core Rule Book, and we’ve been getting questions about how MegaMek will handle the transition. If you’ve been following along, you know we implemented the relevant Playtest rules in MegaMek as they were released. So what happens now?

The simple answer: we will be supporting the Core Rules. But we can’t start coding them until we have final versions in hand. That means we won’t likely have Core Rules support in any release until after GenCon, and it will take us a few months after that to implement everything.

As part of this effort, we’ll also be doing a general cleanup. If you’re not familiar with the concept of technical debt: it’s the accumulated cost of shortcuts, workarounds, and outdated code that builds up over time in any software project. Think of it like deferred maintenance on a DropShip. Skip enough scheduled overhauls and eventually systems start interfering with each other. MegaMek has this in spades. You can’t be a 23-year-old project and not have it.

So as we look at each new rule, our approach will be: implement the new rule, and keep the legacy rule as an option where we can. If we can’t keep both, the legacy option gets removed. I know this is going to upset some players, but we don’t have a lot of choice. There are limits to what a small volunteer dev team can support. We would love to support everything. We just can’t, and we have to take that into account with everything we do.

The good news is that a lot of the Playtest rules are already implemented, and in many cases we just need to reorganize things to convert them into the final rules. But there are also a lot of new rules and corrections to existing rules that we’ll need to incorporate. As we do releases, we’ll call out Core Rules changes as we go.

Note: These release notes highlight key changes in this version. This is not an exhaustive list. For a full breakdown, see history.txt in the docs folder for each project or the change log section at the bottom.

MegaMek

New Features

Advanced Buildings: Now Witness the Firepower

In 0.50.11 we laid the foundation for a multi-stage rework of how MegaMek handles buildings. Proper fortresses, functional turrets, gun emplacements done the right way. This release delivers on that promise. TO:AR Advanced Buildings have arrived in MegaMek, and they bring a complete rethink of how defensive structures work across the suite. If you’ve ever been frustrated in MekHQ base attack missions where the game expects you to either ignore or crew-kill those old legacy Gun Emplacements, this is the fix we’ve been working toward.

What’s New in MegaMek:

• Full Gameplay Support: Advanced Buildings are playable with BV calculations, toHit modifier display on the map, and integration into the force generator
• Princess Support: Princess can attack Advanced Buildings, deploy units to them, and use them tactically. No more hiding behind fortifications from the AI
• Building Sizes: Only single-hex buildings are currently shipped with MM-Data, but the underlying code technically supports multi-hex buildings
• No MML Support Yet: Advanced Buildings cannot be constructed in MegaMekLab at this time. That’s a future goal

Infantry vs Infantry Building Combat:

Breaching! While digging through TO:AR, we came across rules for “Infantry vs Infantry Combat” (TO:AR p.169-174), specifically the special case for inside buildings. This is now fully implemented.

If you (or Princess) move an Infantry unit (CI or BA) into a hex with a hostile Advanced Building, you’ll see a new action during the “Pre-End” phase to initiate infantry-vs-infantry combat. If there are any ongoing combats, a new “Infantry vs Infantry Combat” phase appears where players and Princess can order units to “Reinforce” or “Withdraw” following the rules in TO:AR.

Notably, your Advanced Building’s crew will NOT participate in combat unless you order them to “Reinforce” — the rules describe crew participation as optional. They’re taken prisoner if they don’t join the defense and lose. This lets you garrison your own emplacements and choose to use only the garrison for defense so your building doesn’t take hits. Damage is applied and reported during the end phase report.

What’s New in MekHQ:

• Campaign Option: A new campaign option lets you generate Advanced Buildings instead of legacy Gun Emplacements for base defense missions
• Scenario Objective Resolution: “Preserve” and “Capture” objectives now properly handle Advanced Buildings. A “Crew Killed” building counts as “Alive” for these objectives, which the legacy Gun Emplacements never handled correctly

Bug Fixes for Buildings & Infantry Combat:

• Victory Report: Advanced Buildings now display correctly in the victory report
• Crew Kill Tracking: Buildings with killed crews properly count as crew killed in after-action reports
• Dead Crew Targeting: Buildings with dead crews can no longer be targeted for new infantry-vs-infantry actions
• Reinforce Logic: Fixed reinforcement logic for infantry-vs-infantry building combat
• Casualty Calculations: Fixed incorrect casualty counts for infantry-vs-infantry combat
• Building Power Generators: Fixed cost, BV, and tonnage issues for building power generators

Prosthetics & Augmentations: The Word Made Flesh, Continued

The Manei Domini’s work continues. Building on the significant cybernetic implant implementation in 0.50.11, we’ve expanded the Interstellar Operations augmentation catalog further, this time focusing on prosthetics for conventional infantry:

• Prosthetic Limbs Enhanced (Includes Improved): Full implementation of enhanced prosthetic limbs, giving your augmented personnel meaningful mechanical benefits
• Extraneous Prosthetic Limbs for Conventional Infantry: Enhanced prosthetic limbs are now available for conventional infantry per IO p.84 — because sometimes two arms just aren’t enough
• Prosthetic Tail, Enhanced: Conventional infantry can now sport enhanced prosthetic tails per IO p.85
• Prosthetic Wings (Glider): Glider-type prosthetic wings are now functional
• Prosthetic Wings, Powered Flight: Infantry with powered flight prosthetic wings can now take to the skies. It’s not a Cheap Trick, but your infantry can have Mighty Wings
• Suicide Implants: Implemented per Interstellar Operations. Dark, but canonical

There is still additional work needed on the MekHQ side to fully integrate these prosthetics and augmentations into campaign play. With Iliani’s departure from the project, there’s no ETA on when that work will land. The MegaMek and MegaMekLab sides are functional now.

Cockpit Modifications & Neural Interfaces

We’ve implemented several cockpit modifications from Interstellar Operations. The Direct Neural Interface and Damage Interrupt Circuit (IO p.39) are now fully functional, with DNI providing direct neural control and the DIC giving pilots a buffer against cockpit damage feedback. Enhanced Imaging has been updated to properly follow IO p.69/p.77 rules, and all three systems (DNI, EI Interface, and DIC) now have full integration across applicable unit types.

Quick Reference: What Do I Enable?

Note: If you enable “Track Neural Interface Hardware,” ProtoMeks will become Experimental tech level, as EI is classified as Experimental. If you’re running a campaign or game at Standard or Advanced rules levels, leave this option off to keep ProtoMeks available.

Munitions & Ordnance

Some players just want to watch the world burn. Incendiary LRM munitions are now available and properly included in autoconfig selections. We’ve also added EMP Mines, which can now be deployed on the battlefield.

Combat Systems

MekWarriors can now abandon their ‘Meks under specific conditions per TacOps:AR p.165, with the ejection options reorganized for clarity. Vehicle crews also gain new survival options with the Combat Vehicle Escape Pod (CVEP) implemented per TO:AUE p.121.

Handheld Weapons

Handheld Weapons continue to receive stability fixes from their 0.50.10 debut (see Bug Fixes below).

Quality of Life

• Save Advanced Searches: Your custom search filters are now preserved between sessions
• Elevation Cross-Section Diagram: The Ruler/LOS Tool now includes an elevation cross-section diagram and consolidates the separate rulers into one, making LOS determination more intuitive

• Network Information Dialog: New dialog displays network connection details for multiplayer sessions
• Bot Priority Targeting by Range: You can now set bot priority target IDs by range, giving you finer control over Princess’s targeting behavior
• Board Editor Tagger: New board tagger menu item added to the Board Editor

Improvements

Princess / Bot

• EMP Mine Deployment: Princess can now deploy EMP mines just like other minefields
• Hidden Unit Detection: Fixed Princess incorrectly detecting hidden units through expected damage calculations. No more psychic Princess
• DropShip Pathfinding: Princess will no longer crash DropShips through buildings. She’s reckless, but not that reckless
• Performance: Weapon attack expected damage calculations are now cached, improving Princess’s decision-making speed

Board & Map

Several board and map improvements landed this release. BoardView drawing code has been unified for better consistency, and board files now support copyright header information. Custom deployment settings are clearer and less confusing, fortified hex indicators have been improved to reduce confusion, and the map now properly adapts to new entity types.

Display & Data

Unit readout tables have been improved, and the spotting field of view now correctly shows the Mast Mount elevation bonus. Quirks received proper tooltips with word wrapping and typo corrections, and display issues with the Static Ammo Feed weapon quirk have been resolved. Squadron support has been added for the MUL file format.

Bug Fixes

Combat & Damage

• Artillery Cluster Munitions: Fixed cluster munitions using incorrect hit tables. Above table for ‘Meks and front table for tanks now applied correctly
• Swarm LRMs: Fixed swarm LRMs incorrectly transferring immobile status to secondary targets
• Semi-Guided LRMs: Spotter movement modifiers now correctly applied when using Semi-guided LRMs against spotted (but not TAGged) targets
• AMS Double Engagement: Anti-Missile Systems no longer engage the same incoming attack twice
• Sprinting and Buildings: Sprinting units can no longer automatically hit adjacent buildings
• Sprinting and Clubs: ‘Meks can no longer pick up clubs while sprinting
• LRM Smoke Drift: Smoke from LRM rounds now drifts correctly
• Planted Fields LOS: Line of sight calculations through planted fields now work properly

Movement & Deployment

• Aerodyne Reverse Flight: Aerodyne aircraft can no longer fly backwards in atmosphere. Physics wins
• LAM Fly-Off: Fixed a crash when LAMs attempt to fly off the map
• Bridge Height: Units can once again move on height 0 bridges
• Tripod Turns: Tripod turn handling now works correctly
• Environmental Sealing: Environmental sealing checks now properly applied during movement and deployment
• ACAR Deployment: Fixed formations scheduled for round 0 that were never deploying

C3 / Networking

• C3M BV Bonus: Fixed incorrect BV bonus calculation when C3 Master is connected to C3 Master Master
• Nova Link: Fixed a crash in the /nova link command. As a reminder, players should be using the Nova CEWS GUI during the end phase rather than the command line
• Boosted C3 and AECM: Prevented infinite loop when a boosted C3 master is affected by Angel ECM
• ARAD and ECM: Anti-Radiation missiles are no longer incorrectly affected by ECM

Handheld Weapons

• Lobby Configuration: Fixed crash when configuring a ‘Mek carrying a handheld weapon in the lobby
• Impossible Shots: Fixed HHWs incorrectly flagging valid shots as impossible
• Weapon Drop: Fixed HHWs not properly dropping and remaining available in ‘Mek arms after being discarded
• RAC Ammo Source: Rotary Autocannons in handheld weapons now correctly draw ammo from the weapon entity

Units & Loading

• Command Console Head Hits: ‘Meks with Command Console cockpits and only one crew member no longer apply head hit damage twice to the single pilot
• Zero-Armor Aero Display: Aero units with zero armor no longer incorrectly show as damaged
• Single Fighters Option: Fixed lobby loading for fighters when “Single Fighters Not Capital” option is enabled
• Support Vehicle Loading: Fixed a crash from misinterpreted armor_tech field when loading support vehicles
• TSM Implant Damage Divisor: Fixed TSM implant incorrectly reducing damage divisor when the armor kit already has a divisor of 1.0
• Industrial Mek Heat: Industrial ‘Meks no longer assigned incorrect movement heat
• Silver Bullet Gauss: Hit modifier moved from ammo to weapon where it belongs
• MD Augmentation Availability: Fixed MD Augmentation tech availability checks

Interface & Display

• Cockpit Validation: Interface cockpit validation now works correctly
• Mission Equipment Storage: Removed incorrect validation that limited Mission Equipment Storage to one per unit
• Dazzle Mode: Dazzle mode no longer persists when the option is disabled
• Unit Overview: Fixed unit overview frame thickness display issues
• Bridge Collapse Warning: Bridge collapse warnings now display correctly
• Deployment Weapon Selection: Fixed crash when selecting an un-deployed unit’s weapons during the deployment phase
• Individual Initiative: Initiative bonuses for “Individual Initiative” now correctly come from the team, not the individual

MekHQ Integration

Fixed aerospace units returning to battle after being told not to, along with a related MekHQ POW capture bug. Also fixed a MekHQ save loading failure.

Additional Fixes

• Hand Actuator: Missing hand actuator penalty is no longer cumulative where it shouldn’t be
• Alpha Strike Conversions: Fixed Rail movement, MFB, and Conventional Infantry heat conversions for Alpha Strike
• Ammo Serialization: Fixed ammo mutator shortName and serialization issues
• Faction Advancement: Fixed setFactionsAdvancement and fallbackFactions ordering issues
• RAT Generator: Fixed RAT generator loading failures due to invalid unit type
• Modular Armor Cost: Corrected modular armor cost calculations
• Stealth Armor Validation: Stealth armor now properly validated on superheavy ‘Meks
• MASH on Small Craft: MASH now correctly displays on Small Craft record sheets
• Infantry Armor Panel: Custom armors only shown when rules level is set to Advanced or higher

MegaMekLab

New Features

Prosthetics & Augmentations UI

MegaMekLab now has full construction support for the new Interstellar Operations prosthetics and augmentations implemented in MegaMek this release, including prosthetic enhancements and extraneous prosthetic limbs for conventional infantry (IO p.84). The augmentation view also received validation and UX improvements with clearer feedback when something doesn’t fit.

Cockpit Modifications & Neural Interfaces UI

MegaMekLab construction support added for the DNI, EI Interface, and Damage Interrupt Circuit cockpit modifications implemented in MegaMek this release.

Construction Improvements

• CASE Selector: New CASE selector makes it easier to assign and manage CASE protection across locations

• More Engine Types for Conventional Fighters: Conventional fighters now allow additional engine type selections
• Bay Removal: You can now properly remove bays from units

Record Sheets & Data Display

• Vehicle Effectiveness Rules: Added a menu option to toggle the TacOps:AR p.105 Vehicle Effectiveness rules on Ground Combat Vehicle record sheets
• One-Shot Ammo on Record Sheets: Record sheets now print the ammo type loaded into OS and I-OS launchers. No more guessing what that one-shot launcher is carrying
• Punch Hit Modifier on Record Sheets: Punch hit modifiers now correctly reflect missing hand and lower arm actuators
• Stealth Armor Heat in Heat Profile: Stealth armor heat generation is now included in the heat profile calculations, giving you accurate heat numbers during design
• DPT Calculation with Ammo: Damage-per-turn calculations now factor in ammunition types and include configurable sustained turn counts
• Warship Structural Integrity: Warship SI now displays correctly on record sheets
• Bomb Rack in Equipment Database: Bomb Rack now appears in the MML Equipment Database where you’d expect to find it

Bug Fixes

• FluffTab Persistence: Fixed FluffTab not persisting on save, plus added UI for setting fluff dates on units
• RISC Pulse Module Heat: Fixed duplicate heat from RISC Pulse module appearing in the StatusBar heat display
• Primitive Aerospace Armor: Fixed (yet again) primitive aerospace armor handling
• Patchwork Armor: Various patchwork armor issues resolved
• Armor Type Fallback: Fixed fallback to allowed armor types when an invalid type is selected
• Battle Armor Criticals: Fixed critical slot handling on Battle Armor
• Aero Criticals and Drag-and-Drop: Fixed critical slot issues on aerospace units, including drag-and-drop functionality
• Bay Weapon Critical Tree: Fixed a crash when the refresh listener is null in BayWeaponCriticalTree
• Extra Parenthesis: Removed a stray “)” that was appearing in the UI
• GUI Maintenance: Various GUI cleanup and consistency improvements

MekHQ

New Features

Temporary Crew: Personnel Simplification

A long-requested quality-of-life feature. Certain personnel roles can now be filled with optional temporary crew. This simplifies unit management for situations where you need bodies in seats without the full recruitment process. Temp crew works across multiple unit types including tanks and Battle Armor, with full save/load support.

This is a new feature and went through a round of bug fixes during development. Units with temp crew no longer disappear when loading a save, tanks with temp crew can now deploy properly, and temporary Battle Armor crew now properly fill BA suits.

Canon Diseases & Bioweapons

The medical system expands with canon disease and bioweapon support. This includes herd immunity mechanics, a disease glossary entry, and specific implementations like Ageranium’s Disease and Dobrowski Depression-A Syndrome as character flaws. The Inner Sphere just got a little more dangerous, and not just from autocannon fire.

“Force” Renamed to “Formation”

Throughout MekHQ, what was previously called a “Force” is now called a “Formation.” This aligns terminology more closely with BattleTech usage and should reduce confusion for players coming from the tabletop.

Partial XP Skill Progress

Characters can now accumulate partial XP progress toward skill improvements. No more losing XP because you didn’t have quite enough to cross the threshold. Progress is tracked and carried forward.

Improvements

Campaign Management

• Contract Search Radius: The minimum contract search radius has been reduced from 100 to 1 light-year, giving you finer control when looking for work close to home
• C3i and Nova CEWS in TO&E: Fixed C3i display in the TO&E and implemented Nova CEWS support, so your network-equipped formations display correctly
• Color Explanation Tooltips: Tables throughout MekHQ now include color explanation tooltips — hover to understand what those highlighted rows actually mean
• Campaign Options Iconography: Updated icons for campaign options in 0.50.12
• Campaign Option Badges: Improved badge handling for campaign options
• Surgeon Skill Display: The prosthetic surgery dialog now shows the surgeon’s skill level instead of a raw target number — much more intuitive
• Daily Report Tabs: Category tabs in the daily report no longer highlight when they’re empty
• Salvage Picker Buttons: Confirmation buttons in the salvage picker have been repositioned for better usability
• Hotkey Improvements: Addressed various hotkey issues throughout MekHQ

StratCon

• Mapless StratCon VP Scoring: Fixed VP scoring for Fleet in Being and Refused Engagement scenarios in Mapless StratCon
• Completed Objectives: Fixed an issue where completed StratCon objectives were being invalidated by subsequent scenario losses — your victories now stick
• Advanced Scouting Boundary: Advanced Scouting can no longer scout off the edge of the StratCon board
• Eagle Eyes Rolls: Fixed Eagle Eyes rolls for Advanced Scouting
• Maneuver/Auxiliary Reinforcement Reporting: Fixed roll reporting for maneuver and auxiliary reinforcements

Personnel & Medical

Improved tooltip fetching for academies with graceful failure handling. Transport cost display and calculation semantics have been fixed, along with transport reporting for Conventional Fighters, Fixed-Wing Support, and ProtoMeks.

Bug Fixes

Campaign & Contract

• Contract Generation for Absorbed Factions: Fixed contract generation for factions that have been absorbed by super-states — no more missing contracts because your employer got conquered
• Custom/Unknown Factions: Fixed a crash when loading campaigns with custom or unknown factions
• Force Self-Assignment: Prevented a formation from being assigned as its own subformation — because that’s a paradox, not a TO&E
• Formations Returning from AoO Map: Fixed formations not returning from the Area of Operations map
• Learning Ropes Campaign: Updated the learning ropes tutorial campaign for 0.50.11 compatibility

Combat & Scenarios

Fixed an issue where new pilot hits were being doubled when resolving a scenario. Permanent injuries can no longer be replaced by temporary ones, a double scaling issue affecting unit display has been resolved, and the BotForce Randomizer no longer throws errors or generates nothing when weight class isn’t set.

Personnel & Equipment

• XP Spending Crash: Fixed a crash when spending XP on new skills
• GM Edit Person Dialog: Fixed a crash in the GM Edit Person dialog caused by a missing Enhanced Imaging resource
• Missing Swap Ammo Menu: Fixed the “Swap ammo” menu not appearing for some units
• Armor Location in Salvage: Fixed armor location not displaying when stripping units in salvage mode
• Warehouse Armor Warning: Fixed a false warning about no armor in the warehouse
• MRMS Infinite Loop: Prevented an infinite MRMS loop when an AmmoBin repair can’t be fulfilled
• MRMS Resource Bundle: Corrected resource bundle reference in MRMS service
• Ammo Type Casting: Fixed a type check before casting ammo types to prevent errors

Miscellaneous

• Planet Temperature Data: Fixed a crash when accepting a contract on a planet with missing temperature data
• Academy Tooltip Crash: Fixed an IndexOutOfBoundsException in academy tooltips for mismatched curriculum data
• User Academy Files: Fixed a crash when user academy files replace base academies
• Commander Death: Fixed a missing resource exception when killing the campaign commander
• MASH Rentals: MASH facility rentals now actually work
• Campaign Option Labels: Fixed minor text and label errors in campaign options

Data Improvements (MM-Data)

Our data contributors continue to improve the unit files and game data that drive the MegaMek experience. Highlights from this release:

Unit Fixes & Additions

A variety of unit fixes across all unit types this release, including corrected techbases, fixed ammo loads, updated manipulators and motive types, validation fixes, and new variants like the Rifleman (Legend Killer 2) and Rifleman II (Legend Killer). JumpShip, DropShip, Battle Armor, and Clan unit data all received corrections. We also did a comprehensive fluff data pass improving manufacturer info, model descriptions, and historical context across all unit types.

Campaign & Faction Data

Various faction and campaign data improvements including updated ranks data, corrected force generation ratings and availability data for multiple eras and factions, and supporting data for features called out in the MekHQ and MegaMekLab sections above.

Coming in 0.50.13: March SUCS Data

For those following our collaboration with the SUCS team on Sarna, we’re excited to share that the March SUCS data drop will be incorporated into the 0.50.13 release. This means updated system ownership, coordinates, and faction data flowing into the Interstellar Map. If you haven’t checked out the interactive map on our website, give it a look.

This release includes numerous additional fixes and under-the-hood improvements not individually listed here across all three programs. For a complete list of all changes, please refer to the change log section at the end of these release notes or visit the individual PR descriptions on GitHub.

Technical Stuff

Java 17 and Java 21 are Supported for all 0.50.x Releases

Starting with this release, we officially support both Java 17 and Java 21. Both versions follow the same installation process. Our guide to Updating to Adoptium (Eclipse Temurin Open Source Java) uses Java 17 as the example, but if you’d prefer Java 21, simply select Java 21 instead of Java 17 during installation. Everything else in the directions remains the same.

It’s crucial to read the directions carefully, especially Step 6, which covers a recent change to the Adoptium installer. Make sure to select “Install for all users of this machine” in the Installation Scope.

We continue testing against Java 25 and things look optimistic, but it will likely be later this year before we’re willing to commit to a full move. If you choose to use a Java version beyond 21 that isn’t officially supported, our standard response for issues will be to revert to Java 17 or 21.

WARNING: Java 24 was released (18 March 2025)! If you are running on an older 32-bit OS, DO NOT INSTALL JAVA 24 or later as they have officially dropped support for 32-bit Windows.

Running a Dedicated Server with Docker

Want to host your own MegaMek server? Docker images for MegaMek dedicated servers now support user folders for custom content. For setup instructions, visit the Docker guide on MegaMek.games.

Important: MekHQ Campaign Update Instructions

It is critical to follow these steps to ensure the integrity of your MekHQ campaign when updating between versions. Failure to follow these steps can result in the corruption of your campaign file.

Treat each release as stand-alone; Copy, never Move your data forward from older versions. MekHQ is NOT backward compatible.

1. Make a backup of your campaign and custom files. This is a critical step to prevent data loss!
2. DO NOT COPY MegaMek saves or any preference file from a different version to avoid compatibility issues.
3. Update MekHQ to the latest version. NEVER overwrite the existing folder; always keep each version in its own folder.
4. Re-save any custom presets to ensure they are updated with the new version’s settings.

A Few Reminders

The Milestone System Summary

Please see this link for details on our Milestone release system.

State of the Universe & Development Updates

If you haven’t read our recent posts, we recommend checking out:

• 2026 State of the Universe

User Data Directory

We have a customizable User Data Directory feature that allows you to set a single external directory for storing game resources like units, camos, and fonts, accessible across different installations and versions.

Set up this directory via client settings. A game restart is required for changes to take effect.

Social Media

Join our official MegaMek Discord, our primary community hub for the suite. We offer voice support, individual channels, and assistance for the official public servers. We’re also part of community Discords Everything BattleTech and Classic BattleTech. Find us on Facebook at MegaMek BattleTech and MegaMek.

Contributing

Interested in contributing? Find out how here.

Change Logs (Release Specific) and Download Links

MegaMek Change Log

Full Changelog: View on GitHub Download MegaMek 0.50.12

MegaMekLab Change Log

Full Changelog: View on GitHub Download MegaMekLab 0.50.12

MekHQ Change Log

Full Changelog: View on GitHub Download MekHQ 0.50.12

Hey everyone,

You may have seen an article circulating about MegaMek’s use of AI tools, and some communities are now raising concerns about AI-generated art in the program. We want to address this directly.

We became aware of this article today—the writer didn’t reach out to us before publishing, so this is our first opportunity to respond. We appreciate the chance to provide some clarity.

On AI-Generated Art

Let’s be specific: the only AI-generated art in MegaMek consists of the pilot portrait packs and the PACAR resolution screen.

The portrait packs came at a time when we needed a few thousand faces. People were creating packs using images of movie stars and other recognizable faces, which raised legal concerns. We sourced these images as ethically as we could manage—I sought out an image generation service that used licensed source images for training (not stolen art) and was licensed for our intended use. These images were paid for out of my own pocket and donated to the project. A human artist, Saxarba, then refined them into the final images you’ve been using since 2020—we even said at the time: “A big thanks to Saxarba for taking generic computer generated faces and turning them into a BattleTech feel.”

The PACAR resolution screen was contributed by a developer who is no longer with the project. It was simply a placeholder until we could commission a proper replacement—we’ve now removed it.

All other art in the program—splash screens, tilesets, sprites, and otherwise—has been created by artists who have been paid for their work or have volunteered their time and talent: Sp00ky777, Eldon Cowgur, Saxarba for tilesets, and Deadborder for sprites.

We have no intent to begin using generative AI art in MegaMek. It can’t compete with real artists for quality.

On AI-Assisted Code

Yes, we use AI tools in development. Here’s what that looks like:

• Code Reviews: We’ve used GitHub Copilot for code reviews for some time.
• Data Conversion: We’ve used AI tools for XML-to-YAML conversions and other data tasks, like cleaning up text, grammar, spelling, and formatting.
• Bug Fixes and Features: More recently, I’ve been investigating and exploring the use of AI tools (primarily Claude Code) to assist with writing fixes and implementations—partial implementations, outdated code, and edge cases.

Why We’re Doing This

MegaMek is a 23-year-old volunteer project. No one on the team is compensated for their work. Currently, all the work you see happening in the programs is done by volunteers with limited hours. We have a backlog that grows faster than we can address it. AI tooling allows developers (like me) who can read code but not write it to help fix bugs and implement features that would otherwise sit untouched.

The process is:

1. Code is developed under human direction
2. Tested by human developers
3. Played by Human Test Pilots (QA Team)
4. Reviewed by human developers
5. Checked with Copilot on GitHub
6. Signed off and merged

Every line of code that goes into MegaMek passes through multiple layers of human oversight before it reaches you.

On Transparency

We are an open-source project. Our code, processes, and licensing are all publicly visible on GitHub—every commit, every pull request, every discussion. We use GPL3 for code and CC4 for assets (we moved to CC4 specifically so people couldn’t profit from our assets without citing the source). That’s how this article found the AI labels in the first place.

There’s nothing hidden here—we intentionally label pull requests involving AI tools so we can track that code for future reference if needed. Ironically, the only unlabeled AI code is when a human forgets to tag it.

Moving Forward

We understand that AI is a topic many feel strongly about, and we respect that. The legal landscape is still evolving, and people will naturally come to their own conclusions about what tools and software they’re comfortable with.

What we can say is this: the software itself hasn’t changed. The game still plays the same way it always has. The license is the same. The team is the same. The difference is in some of the tools we’ve used to help us work more efficiently.

Our stance on art remains unchanged: when we need art, we will continue to ask the community for funds and/or pay out of our pockets, pay artists for their work, release the art to the programs, and announce which artists created it so we can encourage people to support them.

MegaMek will continue development. Players who prefer older versions can always access them—v0.49.4 (October 30, 2021) was the last release before any Copilot interactions, and v0.47.11 was the release before the portrait packs (or you can simply delete the portrait folder). We’ll keep building for those who want to come along—and for those who want to contribute art, code, or other skills, we’d welcome the help.

2026 State of the Universe

By Hammer

Before I get into the State of the Universe, I have an announcement.

If you’re wondering what makes a Milestone different from a Development release, check out our Milestone Releases guide.

Since its release, we’ve had remarkably few bug reports, and the couple of minor issues that did come up were easy-to-fix data issues. We have small data patches available on our Discord—check the #announcements channel. If you downloaded the programs prior to January 7, 2026, you can go to the download link and re-download the programs, or get the patches from Discord and patch your release.

If you choose to re-download: with this release, and only with this release, you can safely unzip it over the existing folder. Again, I need to stress—you can only unzip over the same release version. If you want to be really safe, unzip it to its own folder, move your data over, and then delete the old version.

2026 State of the Universe

Following the success of our previous State of the Universe updates, we’re excited to share another comprehensive look at MegaMek. We’re now into our 24th year—still technically alpha software, still committed to that version 1.0 release by the end of the century. Although, as I write this, I suddenly realize we’re now a quarter of the way through the century. We might need to pick up the pace a bit!

Traditionally when we do these, we don’t like to use “I,” because MegaMek is a team—and yes, there is no “I” in team. But I’ll take a moment to provide some context. I’m Hammer, one of the longest-serving members of the team. I began contributing to the projects in 2011, officially joined the team in spring 2013, and in 2024 was volun-told I was the Project Lead by the other developers. My role has evolved over the years—I’ve stepped back considerably from my work as the data guy, and these days I’m something of a Solahma warrior—keeper of the MegaMek Remembrance, tossing out the wish list of things that would be amazing to see happen. Some of that wish list actually happened in 2025, and some of it is happening even as I write this.

Some Thank You’s

My words from previous years still echo true…

On behalf of the Dev team, thank you to everyone who’s contributed to these programs:

• The creators of BattleTech, past and present, whose universe and game mechanics give us something worth building.
• Our emeritus developers, whose past work made everything we do today possible.
• The contributors/test pilots who share their talents and time, consistently raising the bar for what these programs can do.
• Most importantly, our players—your engagement, feedback, bug reports, and shared stories keep these programs alive. You are the heart of MegaMek.

Our Discord server now stands at 5,109 members and continues to grow. We’re one of the larger BattleTech communities out there, and while the Discord server is heavily focused on MegaMek, some of the most active conversations we have are around the universe, the tabletop rules, and everything happening with the Renaissance of BattleTech in general.

I don’t want to call out specific developers, because everybody contributes in their own way. We have people who push huge amounts of code. We have people who maybe only do one feature, but it’s an important feature. We have people who play the game and identify the bugs. The project is about the BattleTech community—it’s not about any individual. Everybody contributes, whether it’s playing the game and talking about it and sharing their experiences, or writing the code and implementing the rules and changes and new ideas and features.

As somebody who’s been with the projects a while, I look around the community—the contributors, the test pilots, the developers, and the content creators who take time out of their day to stream the programs, make videos, and showcase what we do in ways that a still photo simply doesn’t allow. While things can be frustrating and annoying at times, you also recognize that this is something special.

You hear stories of people’s games, and you know that people are going to talk about their experiences for a long time. Every headshot. Every failed piloting check. They’re all part of the story and the narrative that is the BattleTech universe.

I’m just grateful to be part of that, with people who love the game and the universe as much as I do. It brings a big smile to my face to know that we’re a respected part of BattleTech.

2025 in Review

If I had to characterize 2025 in one phrase, it would be: the biggest year we’ve ever had. In my time with the projects, this is the most code we’ve ever pushed, the most features we’ve ever implemented. If you look at what MekHQ looked like at the 0.49.19.1 release and compare it to today, it’s like a different program.

The team has seen some turnover this year. We had developers come in, make a fairly big impact on the programs, and then leave us. I think that’s just the nature of open-source projects. We have people who come in and stay long term, people who drop in and out, and people who come in, do one or two big things, and then leave—because ultimately, we’re still a hobby. But I think the dev team we have now is probably one of the strongest we’ve ever had, both in terms of size and in terms of what they’ve done and accomplished.

By the Numbers

The numbers tell the story: 47 contributors added nearly 8 million lines of code, data, and content across the projects throughout the year. We closed 398 reported issues and pushed over 1,400 bug fixes. Every bit of that is volunteer work.

On the content side, we added 948 new unit files, 433 new map boards, and 52 new ‘Mek files.

Releases

As a reminder: Development releases are our regular updates that may have some bugs but include new features. Milestone releases are versions we’ve identified as particularly stable—safe spots for players who prefer reliability over bleeding-edge features.

*Still accumulating

Sharp-eyed readers will notice we jumped from 0.50.07 to 0.50.10. Seven ate nine—or rather, Gradle did. Our build system flat-out refuses to compile versions ending in .08 or .09. Sometimes the quirks aren’t just in the ‘Meks.

The v0.50.06 Milestone drove approximately 10x the downloads of our development releases. MekHQ continues to be the primary download at about 76% of total downloads, confirming that campaign play is central to how people experience the MegaMek suite.

The big efforts of 2025 were landing the v0.50.06 Milestone in May and completing the licensing reorganization in Q3. With 0.50.07, all of our code moved to GPL 3, and all of our data moved to Creative Commons—a significant undertaking that positions us better for the future.

I need to call out and thank Tex for taking on the absolute Herculean job of leading much of the code refactoring work that made this possible. If you’re not familiar with the term “refactoring,” think of it as pulling every single item out of a closet, organizing everything, and then putting it all back in a new, more logical order. The other developers helped, chipped in, and supported this effort—and it shows in the stability improvements we’ve seen.

Community Reach

MegaMek reached players in 166 countries in 2025. Our biggest audiences came from the United States, Canada, Germany, the UK, and Australia—but we also saw players from Russia, Poland, Spain, the Philippines, Brazil, and beyond.

MegaMek: The Digital Battlefield

What’s New in 2025

Looking back on 2025, there are so many things we implemented, changed, and improved—in every release. When we looked at the changelog for 0.50.07, it was literally too large to include in a single blog post.

At broad strokes, what we’ve been really happy to see is a general improvement in stability. We’ve modernized a lot of old systems to bring them in line with errata. Key additions:

• Playtest Rules — Packages One, Two, and Three (Gear), all optional under Game Options
• Handheld Weapons — Finally playable in v0.50.10
• Picking Things Up — ‘Meks carrying small vehicles or BA squads
• Lift Hoists — Now functional with MekHQ integration
• ARAD Missiles — Anti-radiation ammo for SRMs, LRMs, MMLs
• Manei Domini Cybernetics — Fully aligned with Interstellar Operations
• Minimap improvements — Sensor range, facing displays, UI enhancements
• GM Tools — Headless client and Commander GUI

Force Generation continues to improve with more era-appropriate and varied results.

MegaMekLab: The Engineering Bay

We’ve had so many improvements to MegaMekLab in 2025 that while cosmetically you may think the program looks the same, the functionality has transformed.

The Tab Revolution

The biggest change is our reimplemented tab system:

• Open multiple units in separate tabs
• Drag and drop to reorder or undock into separate windows
• Real-time preview — watch the record sheet update as you edit
• Middle-click to close, double-click empty bar to reattach all

Multiple designs open, side-by-side comparisons, Alpha Strike card previews—it transforms how you work.

Other Key Improvements

• Drag and drop unit files from outside the program
• Handheld Weapons record sheets
• Undo/Redo/Reload under Edit menu
• Asynchronous rendering — improved performance on complex units
• Quirks tab rework — better organization

Gothic Support

Yes, we have decided internally that we will support Gothic. But for us to fully support Gothic, we need full construction rules to come out. The ‘Meks are pretty straightforward, but without rules for Abominations, we’re not in a position to create an Abominations construction section to produce record sheets.

MekHQ: The Command Center

If there is a program that changed the most in 2025, it’s MekHQ. We are now the ultimate way to play AccountTech in BattleTech—you’re not just leading a unit into battle anymore, you’re managing people with actual characters.

The Big Changes

Against the Bot Retired: After more than a decade of service, AtB was officially retired in v0.50.10. For many, it feels like losing an old comrade—it’s been part of MekHQ’s identity since Neoancient integrated it in 2014. But its spirit lives on in StratCon, now stronger and more flexible than ever. To the original spreadsheet pioneers: thank you. Against the Bot served with honor.

StratCon Feature Complete: We now consider StratCon feature complete. For those who preferred AtB’s simpler approach, we introduced two new modes:

• Mapless Mode — StratCon without the campaign map, but with better OpFor generation, refined salvage and logistics, convoy and rescue missions
• Single Drop Mode — Designed for multiplayer groups splitting into BluFor and OpFor

Both modes are designed with streamers and large multiplayer campaigns in mind.

New Features & Systems

• Alternative Advanced Medical System — Expanded injuries, 19+ procedures, prosthetics, disease mechanics
• Mercenary Auction System — Bid on equipment instead of random free units
• Enhanced Ronin Event — Recruit approaching ronin for Support Points
• Veteran Rank SPAs — Free SPA at Veteran (2% chance of Flaw instead)
• Automatic Campaign Upgrader — No more manual version migration steps
• Daily Report Tabs, Expanded Glossary, Quick Train, Auto-Tech Assignment, Second-in-Command
• Campaign Options IIC — Significant updates for better option management and campaign customization

We deprecated Scrounge and added procurement restrictions as a campaign option.

RPG Integration

We’re bringing the game closer to A Time of War with an evolving advanced character builder. For those who hate that level of detail, we’re simultaneously developing “Blob Crews”—the platoon commander and 27 shadowy figures in the background, rather than 28 individual personalities.

Design Philosophy

Many systems we’ve introduced address the power curve problem. Campaign Operations doesn’t cover everything, and the automation in MekHQ lets you play games quickly and accumulate C-Bills and experience at phenomenal rates. Our homegrown systems—medical, logistics, convoys—are designed to give you agency through meaningful choices.

We’re trying to create a sense of command—and the most difficult choice a commander faces is whether to fight at all. History is full of battles that should or shouldn’t have been fought, decisions that ultimately shaped outcomes far beyond the battlefield. That’s what we’re evolving MekHQ to model: the weight of command, where sometimes the only winning move is not to play. When you see it that way, everything starts to link together.

MekBay: The Web Evolution

MekBay’s reception has been absolutely incredible. Launched in September 2025, it’s grown steadily—and just a few days ago we added Alpha Strike support, which created quite a buzz.

For those not familiar, see our announcement post: Introducing MekBay: MegaMek’s Web Evolution

Why MekBay?

MekBay started with a simple request we heard for years: “I wish MegaMek was usable on mobile.”

We couldn’t port MegaMek itself to mobile—the codebase is too complex. But we could bring core functionality to the web: the unit database, force building, record sheet generation. MekBay is the result. It’s not a replacement for the desktop programs; it’s a companion that meets players where they are.

What Players Are Using It For

• Unit database access and force building
• Record sheet generation from any device
• Alpha Strike support (just added)
• Mobile access and mini tracking

We knew it would be popular. We didn’t anticipate this popular.

How MekBay Works

MekBay shares databases with MegaMek—our unit files drive the data. Plans include MUL file compatibility and eventually custom unit support between platforms.

Unlike desktop releases, MekBay updates daily. I’ve seen players request features on Discord and Drake push them out hours later. If you tried it in September and haven’t looked since, check it out again.

For the record, we have no plans for a web-based MegaMek.

Technical Updates

Now for the stuff that makes the techs happy.

Java 17 Transition

With the release of 0.50.0, we transitioned to Java 17. To be honest, we held our breath. I remember the chaos when the community had to move from Java 8 to Java 11—it wasn’t fun. That was compounded by Oracle’s decision to make Java open-source, which created huge confusion.

The good news is the move to Java 17 was relatively painless. We were positioned with good tutorials, we had community members generous enough to make YouTube videos on how to update, and our Java quick-tip (which gets lots of use on Discord) really helped players upgrade seamlessly.

Looking Ahead: Java 21 or Java 25?

We try to follow the LTS (Long Term Support) versions of Java. Java 17 entered long-term support in September 2021 and has extended support through September 2029. Java also does its best to stay backwards compatible.

In the previous State of the Universe, I mentioned we’d evaluate the decision to move to Java 21 in September 2026. Java 21 was released in September 2023 with long-term support until 2031. Quite a few players are currently running the programs on Java 21 without issues, so we anticipate good stability.

One thing we’re currently studying: should we jump straight to Java 25? Java 25 was released in September 2025 with support until 2033. Traditionally, MegaMek has lagged behind LTS versions, but as Java evolves, it introduces new features we can use to further optimize and improve the code.

As of this State of the Universe, our intention is to stay with our Java 21 plan—sometime in the winter of 2026, we’d likely release a version requiring Java 21. But there’s a chance we’ll say “no, we’re going straight to Java 25.” We’ll have more on this later this year, probably making decisions in the fall based on our testing.

If you like running bleeding edge, feel free to grab Java 25—it’s available now. If you have bugs or issues, you’ll get us saying it’s not officially supported, but we’d appreciate any feedback.

YAML Migration

We’re continuing our migration toward YAML. In 2025, we transitioned our system data to the new format and released an alpha Systems Editor in 0.50.04. Instead of navigating massive XML files, each system now has its own dedicated YAML file containing basic data, population changes, faction histories, and SICS codes all in one place. This makes it significantly easier for players and contributors to view and modify system information.

We’d like to start moving our equipment files to YAML this year, though that’s still in the planning stage.

What does this allow us? If we can land the YAML conversion and rework some creaky old code, it would finally open the door for custom weapons and equipment within some parameters. More on this if we can get some architecture in place—probably won’t hear more until later this year.

Under the Hood

Some changes are invisible to most players but represent significant code improvements.

User Data Directory: We added a customizable directory feature that lets you set a single external location for storing game resources—units, camos, fonts, and more. This directory is accessible across different installations and versions of MegaMek, MegaMekLab, and MekHQ. No more copying your custom files between versions.

Damage Manager: The new Damage Manager will soon become the only Damage Manager, replacing legacy code that’s been with us for years. As one of our developers put it: “The DamageManager is dead, long live the DamageManager.” These kinds of refactoring efforts improve stability and make future development easier.

2025 Misses

It’s important to reflect on the year, acknowledge what we missed, and learn from those experiences.

CASPAR

Our biggest miss was CASPAR. It represents the classic problem with open-source projects. We had a very skilled developer come in who had the capabilities to take Princess further—but who also had the ability to develop something new, which was CASPAR. But like the curse of a lot of open-source projects, someone comes in with the best intentions, and then real life kicks in, and it turns out we couldn’t accomplish it.

In hindsight, we announced CASPAR too soon. But we felt we had to—CASPAR required game logging to study how Princess plays, and we weren’t going to collect that data without telling players first.

As for Duchess—the concept of an overarching AI that Princess would work for, specific to the StratCon environment to help direct strategy—it remains just that: a concept. I’m not going to say Duchess is dead, because it never really materialized in the first place. It was from those Duchess conversations that CASPAR emerged.

So as I sit here today, we have missed opportunities with Princess. Our plan is to send her back to Blackjack this year for some continued improvements. In particular, we’re interested in her behaviors around hidden units and improving her fire control decisions by incorporating variables we know she’s missing—things like quirks. We also have some ideas to explore around improving her use of artillery. But this is all in the planning stage, and we’ll have to see how it plays out through the year.

Story Arcs and the Systems Editor

We have one Story Arc—”Young Wolves”—and it’s aging. Again, an example where a committed developer came in, did a lot of work, and unfortunately real life took them.

Story Arcs is in an interesting spot. When that developer came back in early 2025 and we talked about what needed to happen, there was a realization that we needed to do system work before Story Arc work—because stories take place in systems. This led to close collaboration with the SUCS team on Sarna, which started the process of standardizing data and putting in an alpha Systems Editor.

But I’m not sure looking at 2026 where this will play out. We are still committed to Story Arcs. We are still committed to a Systems Editor. We still want to support players with their alternate universe play. But if I’m being honest, the regular BattleTech universe is huge, and that has to be our priority.

That said, we recognize the Systems Editor isn’t just for alternate universe players—even regular campaign players want the ability to update control of various systems as their campaigns progress. So while Story Arcs might not move forward this year, we are exploring ways to get the Systems Editor working.

What does Story Arcs need? Someone who can come in with strong skills to write an editor—because manually writing a Story Arc is too complicated. For the Systems Editor, we need someone with strong knowledge of MekHQ code who can step in, look at the existing code, and get it working.

Lessons Learned

Something you’ll probably see going forward: we had a lot of excitement for things, which led us to announce a lot of things in 2025. I think you’ll find that we’re going to be less inclined to announce big things until they’re well in development and at a point where we can announce them in a way that we know we can get them to the finish line.

Because every time we make a commitment and don’t accomplish it, I take that personally. And I know the other devs feel it as well. It adds a level of stress and pressure that an open-source project can’t sustain.

Looking Ahead to 2026

What does 2026 hold? We’d love to say we’re going to do better than we did in 2025, but that’s going to be a little challenging this year. We have a few developers currently away or planning to take time away from the project, and that always slows development.

With v0.50.11 becoming a Milestone, it puts us in a good position to have a few releases where we can be a bit shaky. Speaking for myself, I intend to modernize some of our older equipment and introduce new equipment.

We’d safely anticipate that in 2026 we’ll probably have four or five releases. We’re trying to keep a pattern of a release every two months, but that varies based on developer contributions and availability.

On the Roadmap

We have several projects we’re confident will land in 2026: the Advanced Character Builder (ACB) for deeper RPG integration, a revamped ranks system, and a new company generator. The initial Espionage system should arrive early this year. TO:AR Advanced Buildings are already available in MegaMek and being tested in MekHQ for base defense missions.

Under the hood, the new Damage Manager will become the only Damage Manager—most players won’t notice, but it replaces legacy code and positions us for future work.

We still want to look into Large Naval Craft, Mobile Structures, and space-to-surface combat, but being honest, we aren’t sure if those will land for a while. As always with a volunteer project, priorities shift based on who has time and energy.

The Big Variables

Everyone’s always interested in super-secret projects and major announcements. Yes, we have things we’re discussing internally that we’re not prepared to announce publicly yet—across all the projects. But we don’t have anything we’re prepared to officially tease or announce at this point. There are plans.

One big variable for us is what happens when Catalyst releases the next rule set based on the playtest. Depending on how comprehensive those changes are, it could take us a few releases to get through all of that.

As we look at 2026—because we’re a volunteer project—things can change and do. You never know when you’re going to lose someone or gain someone who can be instrumental in changing the projects. So while we always have ideas and concepts, we also have to be realistic about what we can do. We’re not a professional software development house with hard timelines.

Pay attention to our blog and, most importantly, hang out in our Discord. We pay close attention to what players say and ask for.

But as we look way out into 2027, I’m hopeful and optimistic that we’ll have some really exciting things—either done or announced—to celebrate 25 years of MegaMek.

Closing Reflections

Looking back on 2025, I’m proud of what we’ve built and how the community has grown alongside it. BattleTech’s resurgence is Catalyst’s celebration, but knowing MegaMek plays a part in that success means a lot. Thank you for playing MegaMek—for your engagement, your feedback, and your passion for the universe. Without you, this would just be a program on GitHub that a few people download.

If you’re reading this and haven’t looked at the programs in the last few years, I invite you to give them a try again. While parts of the programs still look and feel like 2000s accounting software, I think you’ll find a surprising amount of depth and fun within them.

And for those of you who’ve never left us—thank you. Every battle report, every bug ticket, every “this doesn’t match the rulebook”—it all matters. You’ve kept this project alive for 24 years.

I still look forward to the day when I can play Operation LIBERATION—from space to surface—as a campaign. We’re not there yet. But that’s the thing about MegaMek: we’re not going anywhere. Drop by our Discord to share your battle stories, report bugs, or talk BattleTech. There’s a place for you here.

Seyla!

The statistics in this post were compiled from GitHub API data, Git logs, and Google Search Console analytics as of January 7, 2026.

Well, that was a fast turnaround! Just a few weeks after 0.50.10, we’re back with version 0.50.11. Don’t let the quick cycle fool you—this release packs a solid punch with critical bug fixes, quality-of-life improvements, and a significant push on cybernetic implant implementations.

We believe 0.50.11 has a strong chance of achieving Milestone status, though we’ll need a couple of weeks of community testing to make that final determination. If you’ve been waiting for a stable jumping-off point, keep an eye on this one.

Note: These release notes highlight key changes in this version. This is not an exhaustive list. For a full breakdown, see history.txt in the docs folder for each project or the change log section at the bottom.

MegaMek

This release brings a wave of cybernetic implant implementations, quality-of-life improvements, and fixes for some bugs that have been lurking in our tracker for years.

New Features

Cybernetic Implants: The Word Made Flesh

The Manei Domini would be proud. We’ve implemented a significant portion of the cybernetic implant rules from Interstellar Operations, bringing the Master’s blessed augmentations to MegaMek:

• Sensory Implants: Cybernetic Sensory Implants for Infantry (IO pg 78), Multi-Modal Sensory Implants, and Enhanced Multi-Modal Sensory Implants
• Communication Implants: Boosted Comm Implant base benefits now functional, plus fixes to existing cybernetic communications implants
• Neural Interfaces: Prototype Direct Neural Interface (IO pg 83), VDNI/BVDNI implementation fixes (IO pg 71), and Triple-Core Processor (TCP)
• TSM Implants: Missing implementations per Interstellar Ops now added
• Gas Effusers: Cybernetic Gas Effuser (Pheromone) and Toxin variants (IO pg 79)
• Dermal Camo Armor: Now fully functional in gameplay

Whether you’re fielding a Frail against unsuspecting opponents or just want to see what all those implant options actually do in combat, the tools are now at your disposal. Peace of Blake be upon you.

Buildings: The Foundation is Laid

This release begins a multi-stage rework of how MegaMek handles buildings. The groundwork here will eventually bring TacOps building rules to full implementation - proper fortresses, functional turrets, gun emplacements done the right way, and more. There’s more to come, but this is a significant first step toward making defensive structures work as intended.

Quality of Life Improvements

• Round & Phase Display: The window title now shows the current round number and phase - no more losing track mid-game
• Lay Mine Button: ‘Meks and ProtoMeks now have a dedicated button for mine deployment
• Obsolete Quirk: Now fully functional in gameplay - your aging Star League relics will feel appropriately past their prime
• Autoconfig Munitions Fix: Autoconfig no longer selects illegal or ineffectual munitions, making unit setup cleaner
• Aerospace Climb Out: Added vertical map exit at altitude 10 for aerospace units
• Variable Range Targeting Dialog: New dialog makes VRT selection clearer
• PACAR MUL Export: PACAR now generates a MekHQ-usable MUL file at the end of automated resolution, making it easier to bring results back into your campaign

Rules Fixes

• Crippling Damage: Updated per TW Errata v11.01
• Angel ECM Dual Mode: “ECM & ECCM” mode now correctly applies both effects, not just ECCM
• Nova CEWS: Now compatible with Null Signature System
• Tripod Physical Attacks: Now correctly restricted to front arc
• Hot-Loaded Missiles: Launchers now explode when critically hit, as they should
• BA Pop-Up Mines: Now deal damage per mine, not per squad
• BA Swarm Attacks: Zero-damage swarm attacks now correctly roll for critical hits
• Fighter Squadrons: No longer take “high damage threshold” critical hits per Strategic Operations
• Physical Attacks vs Prone ‘Meks: Now resolved correctly
• Non-Fusion ‘Mek Heat: BattleMeks with non-fusion engines now generate movement heat

Bug Fixes

• Handheld Weapons: Fixed mode switching throwing errors or switching incorrect equipment
• Direct Blow Damage: Fixed incorrect rounding of additional damage
• Multiple TAGs: Fixed issues when firing multiple TAG systems
• Rapid-Fire AC Special Ammo: Rapid-fire autocannons were losing special ammunition effects when fired in rapid-fire mode. This has been fixed - your precision or flak rounds now work as intended regardless of fire mode
• Bridge Movement: Fixed walkability problems on bridges
• Building Scaling: Units can no longer scale to roofs of adjacent buildings that are too tall
• MG Arrays: Now properly link for ProtoMeks
• Radical Heat Sinks: Target number now correctly reduces on inactive turns
• Capital Weapons: Modifier now applies to DropShips under 500 tons
• Screen Launchers: Cluster damage now calculated correctly
• LAM Fixes: Fixed aerospace strafing bug; LAMs no longer suffer +3 to-hit on mode change turns; stacked ASF LAMs can now transform
• Aerospace Detection: Fixed visual detection on both ground and non-ground maps
• Area Effect Visibility: Units are no longer incorrectly revealed by AE attacks
• Picked Up MechWarriors: Now properly displayed and reset on unit add
• Pre-0.50.0 Units: Fixed loading issues with ProtoMeks and BattleMeks created before 0.50.0

This release includes numerous additional fixes and improvements. For the complete changelog, see GitHub.

MegaMekLab

A lighter release for MegaMekLab this cycle, focused on construction rule fixes and record sheet improvements.

Improvements

• Obsolete Quirk Implementation: The Obsolete quirk is now available in MegaMekLab, allowing you to properly flag older designs
• K-F Adaptor & Modular Space Station Descriptions: Updated option descriptions to provide better clarity on these construction options

Bug Fixes

• Dermal Armor Mutual Exclusion: Dermal Armor and Dermal Camo Armor are now properly mutually exclusive - you can no longer equip both
• Battle Armor Jump Boosters on Record Sheets: Jump Boosters no longer incorrectly appear on Battle Armor record sheets
• Handheld Weapon Enhancements: Weapon enhancements are now properly linked on Handheld Weapon record sheets

This release includes additional under-the-hood improvements not listed here. For the complete changelog, see GitHub.

MekHQ

This release packs a lot of fixes and quality-of-life improvements. We’re highlighting the key changes below, but for the complete picture, check out the full changelog linked at the bottom.

UPGRADE WARNING (Pre-0.50.10 Campaigns Only): If you are upgrading from a version prior to 0.50.10 and use VTOL or wet naval vehicles, it is vital that you do not upgrade while in transit. If you do, the upgrade process will convert ALL of your VTOL and Naval crews into ground crew. Campaigns already on 0.50.10 or later are unaffected.

Major Features

AutoTech

Joining Quick Train and AutoInfirmary, a new MekHQ Client Option has been added. When enabled, MekHQ will automatically assign techs to unassigned units at the start of each day. The most skilled characters are picked first, and no character will be assigned more than two units.

I’m the Captain Now

You can now designate a second-in-command, just like you assign a campaign commander. If your commander meets an unfortunate end (cockpit crit, resignation, or otherwise), the second-in-command automatically takes over and a new second-in-command is chosen. Succession planning - it’s not just for Great Houses anymore.

Scenario Map Sizes Rework

Scenario map sizes have been completely rewritten. Most scenarios will now generate at around 2x2 map sheets, with some reaching 2x3. As unit counts increase, maps expand horizontally rather than vertically. This keeps engagement ranges consistent while supporting truly massive battles. A new campaign option lets you adjust the scale if needed, but we recommend trying the defaults first.

Buying Off Flaws

You can now spend XP to remove Flaws. The cost equals what you would have earned by taking the Flaw normally - so it’s expensive - but it means a bad roll on Veterancy Awards is no longer career-ending.

Critical Bug Fixes

• Tech Acquisition: Setting your Acquisition Skill to “Any Tech” no longer breaks MekHQ
• Faction Standings: Reloading a campaign was resetting accolade data, trapping campaigns in a “someone important noticed you” limbo. Fixed - expect faction standings events to progress properly now (may take 3-6 in-game months for old data to clear)
• Field Control Dialog: Fixed a Java-related bug where the end-of-scenario dialog sometimes wouldn’t display
• Education: Fixed errors when selecting characters with certain education data; characters with permanent injuries can now attend education

Notable Improvements

• Initiative Fixes: Initiative modifiers now correctly transfer from MekHQ to MegaMek. Princess will have initiative modifiers again - and so will you
• Personality Flaws: Several changes to make flaws like Berserker less disruptive. Characters constantly losing their minds? Put them on Leave between contracts. (Medication option coming in 0.50.12)
• Injury & Aging Effects: Now affect Attribute Scores rather than skills directly, making them less crippling
• Post-Scenario Bugs: Fixed the deployment zone bug and several other issues where information was incorrectly retained between scenarios
• Tabbed Daily Reports: The tabs introduced in 0.50.10 are now fully implemented as filters. Pre-0.50.11 behavior available in MekHQ Client Options (but not recommended)

Additional Changes

• Multi-Tech: Techs can now hold multiple tech professions (e.g., MekTech and Mechanic)
• Report a Bug Button: Quick access to open bug reports. No report means no fix!
• Contract Market Fixes: Profit display corrected (was visual only); columns now sort properly
• Quick Train Upgrades: Can now train additional skills, plus under-the-hood improvements
• New Surgeries: More prosthetic and implant options for Alternate Advanced Medical. Legality now affects pricing
• Campaign Upgrades: Rewritten to be nearly instant and more reliable

For the complete list of changes, see the changelog on GitHub.

Technical Stuff

Java 17 is Required for all 0.50.x Releases

Starting with version 0.50.0, Java 17 is REQUIRED to play. We’ve updated our guide to Updating to Adoptium (Eclipse Temurin Open Source Java) with detailed instructions.

It’s crucial to read the directions carefully, especially Step 6, which covers a recent change to the Adoptium installer. Make sure to select “Install for all users of this machine” in the Installation Scope.

We will continue using Java 17 until Fall 2026. If you choose to use a Java version beyond 17, it isn’t officially supported, and our standard response for issues will be to revert to Java 17.

WARNING: Java 24 was released (18 March 2025)! MegaMek still only requires Java 17, but if you are running on an older 32-bit OS, DO NOT INSTALL JAVA 24 as it has officially dropped support for 32-bit Windows.

Looking Ahead: We’ve added testing against Java 25 LTS in this release as we prepare for future upgrades. No action needed on your part - just know we’re planning ahead.

Running a Dedicated Server with Docker

Want to host your own MegaMek server? Docker images for MegaMek dedicated servers now support user folders for custom content. For setup instructions, visit the Docker guide on MegaMek.games.

Important: MekHQ Campaign Update Instructions

It is critical to follow these steps to ensure the integrity of your MekHQ campaign when updating between versions. Failure to follow these steps can result in the corruption of your campaign file.

Treat each release as stand-alone; Copy, never Move your data forward from older versions. MekHQ is NOT backward compatible.

1. Make a backup of your campaign and custom files. This is a critical step to prevent data loss!
2. DO NOT COPY MegaMek saves or any preference file from a different version to avoid compatibility issues.
3. Update MekHQ to the latest version. NEVER overwrite the existing folder; always keep each version in its own folder.
4. Re-save any custom presets to ensure they are updated with the new version’s settings.

A Few Reminders

The Milestone System Summary

Please see this link for details on our Milestone release system.

State of the Universe & Development Updates

If you haven’t read our recent posts, we recommend checking out:

• 2025 State of the Universe
• Looking Ahead and Looking Back: MegaMek Development Update 2025

User Data Directory

We have a customizable User Data Directory feature that allows you to set a single external directory for storing game resources like units, camos, and fonts, accessible across different installations and versions.

Set up this directory via client settings. A game restart is required for changes to take effect.

Social Media

Join our official MegaMek Discord, our primary community hub for the suite. We offer voice support, individual channels, and assistance for the official public servers. We’re also part of community Discords Everything BattleTech and Classic BattleTech. Find us on Facebook at MegaMek BattleTech and MegaMek.

Contributing

Interested in contributing? Find out how here.

Change Logs (Release Specific) and Download Links

MegaMek Change Log

Full Changelog: View on GitHub
Download MegaMek 0.50.11

MegaMekLab Change Log

Full Changelog: View on GitHub
Download MegaMekLab 0.50.11

MekHQ Change Log

Full Changelog: View on GitHub
Download MekHQ 0.50.11

Welcome to version 0.50.10! If you’re wondering what happened to 0.50.08 and 0.50.09—well, seven ate nine. More accurately, our build system (Gradle) decided it doesn’t like those version numbers and flat-out refuses to compile them. Rather than argue with our tools, we’ve declared them “The Builds That Shall Not Be Named” and moved on. Sometimes you just have to pick your battles, and this wasn’t one worth fighting.

Version numbering aside, we thought 0.50.07 was a big build—and we had three months to work on it. We’ve done almost as much in six weeks. There’s an enormous amount here—so much that we can no longer present everything in the release notes. We’re highlighting key features below, but we strongly encourage you to explore the full changelogs linked at the bottom.

This release marks two milestone moments for the project. First, after more than a decade of service, Against the Bot has been officially retired. AtB served the community well, but StratCon now offers everything it did and more with active development. It’s the end of an era, but it clears the path for MekHQ’s future. With this release, we also consider StratCon feature complete—other than bug fixes, we have no plans for new features.

Second, Handheld Weapons are finally playable. We teased something epic coming this fall, and this is it. After being construction-only in MegaMekLab for several releases, ‘Mechs can now wield handheld weapons in actual gameplay. Combined with the ability to pick up and carry small vehicles or Battle Armor squads, this opens up tactical possibilities we’ve never had before.

Beyond these headlines, you’ll find Playtest Package 3 implementation, Nova CEWS with a proper UI and lobby configuration, functional Lift Hoists, new ammunition types, and fixes for some of the oldest bugs in our tracker. MekHQ brings Alternative Advanced Medical systems, CamOps Salvage rules, facility renting, and major StratCon enhancements including Mapless and Single Drop modes.

Note: These release notes highlight key changes in this version. This is not an exhaustive list. For a full breakdown, see history.txt in the docs folder for each project or the change log section at the bottom.

MegaMek

Major Features

Handheld Weapons: Finally Playable!

After being construction-only in MegaMekLab for several releases, Handheld Weapons (HHW) are now fully functional in gameplay. This represents significant work to bring these weapons from the design bay to the battlefield.

But that’s not all - with the TO:AR “picking up stuff” option enabled, ‘Mechs can now carry very small vehicles or Battle Armor squads in their arms. Think of it as giving your Atlas its own Tonka toy. While you can’t throw them yet (that’s a future goal), the foundation is in place for some interesting tactical possibilities down the road.

Lift Hoists: Now Functional

Lift Hoists have moved from theoretical equipment to working battlefield tools. Units equipped with lift hoists can now use them in gameplay, with full MekHQ integration for campaign play.

Playtest Package 3 Implementation

Following our implementation of Playtest Packages One and Two, we’ve now added support for Playtest Package 3 - Gear. As with previous packages, these rules are implemented as optional settings and are turned off by default.

Enable them in Game Options > Basic Options. Look for the Playtest Package Three options.

As always, we’re an open-source, fan-based project. If you provide feedback to Catalyst stating your experience was based on MegaMek implementation, they may choose not to accept that feedback. We strongly encourage testing rules on tabletop and providing feedback through the channels Catalyst has defined in their playtest documents.

Anti-Radiation Ammunition (ARAD)

We’ve implemented Anti-Radiation Ammunition (ARAD) for SRMs, LRMs, and MMLs. These missiles home in on active electronic systems, providing a tactical option against units relying on electronic warfare equipment. Unlike Listen-Kill missiles, ARAD missiles maintain their full range and damage potential and aren’t easily confused by ECM. However, they’re incompatible with Streak or Artemis systems. ARAD ammo is included in autoconfig support.

Nova CEWS: Complete Implementation

We’ve delivered a comprehensive implementation of Nova Composite Electronic Warfare System (Nova CEWS) rules per Interstellar Operations: Alternate Eras. This includes BV cap enforcement (the 35% bonus cap was previously missing), lobby network persistence fixes (networks configured in lobby now properly persist when game starts), a new in-game network management dialog for the End Phase, and C3 connection line display fixes across all game phases.

Notable Bug Fixes (these fix some of the oldest bugs we have)

Combat, Targeting & Movement

• Dead entities can now have their missiles targeted by AMS - no more free passes for missiles from destroyed units
• ASFs are now correctly targeted by ground units
• Air-to-Ground LOS now works properly even when aircraft end their movement far away
• Hidden units no longer visible when they shouldn’t be
• Pointblank Shots now work properly
• Aero non-BAP sensor range corrected
• VTOLs can now load units at end of turn
• Zipline dropping now uses target position rather than starting position

Edge & Special Abilities

• Edge can now only be used once per roll, enforcing the official rule
• Edge can no longer be used to re-roll crit locations when only one viable location remains
• Tactical Genius no longer causes game freezes

Quality of Life

• Aero Maneuvers tooltips: Hovering over maneuver options now displays detailed information including requirements, thrust costs, control modifiers, and effects

MegaMekLab

Bug Fixes & Improvements

• Battle Armor Detachable Weapon Packs now properly display weapons on record sheets
• Stealth armor no longer incorrectly flagged as Fixed Mount Unit (FMU)
• QuadVee flank BV now correctly calculated when equipped with supercharger
• Quirks tab layout aligned with MegaMek’s 3-panel design for consistency
• Fixed ground movement table display
• Fixed missing faction availability for Clan ‘Mechs with Inner Sphere names

Infrastructure

• Significant work on MekBay data integration including fluff data, systems data, cargo data, and Alpha Strike data

MekHQ

Major Features

Against the Bot: End of an Era

After more than a decade of service, Against the Bot (AtB) has been officially retired. StratCon is now the supported campaign system, offering everything AtB did and more with active development. The migration is straightforward - StratCon uses the same underlying campaign structure with a more robust codebase.

AtB was implemented when MekHQ was in its infancy, and over time it became so intertwined with StratCon and base MekHQ that fixing one often broke another. This retirement removes legacy code issues and lets us improve StratCon without cascading issues. Related cleanup includes deprecating the old AtB Ship Search in favor of the expanded Unit Market.

Alternative Advanced Medical (AAM)

This new optional system adds expanded injury types with detailed effects, full prosthetic and implant surgery options (over 19 elective procedures), disease mechanics with an inoculation system, and location-specific injuries with appropriate healing modifiers. Characters with too many advanced implants may experience mental and physical health degradation.

AAM will see significant expansion in coming versions - this is just the foundation.

CamOps Salvage Rules

New optional salvage rules bring MekHQ in line with Campaign Operations. When enabled, you’ll need dedicated salvage forces in your TO&E. These forces deploy to scenarios, and following battle resolution, you use them to recover your salvage. The system includes a Salvage Force Picker, Salvage Tech Picker, and salvage return delays based on deployment time.

This is a fairly involved system - we recommend reading the official CamOps rules and experimenting before using it in an active campaign.

Facility Renting

When accepting contracts, you can now rent facilities instead of maintaining permanent units for support functions. This covers MASH Theater capacity, Field Kitchen capacity, and security personnel. Pay a fee, get the benefits.

You can also rent Maintenance Bays and “Factory Conditions” for your units while off-contract or on garrison contracts (any contract ending in “Duty” except Relief Duty, plus Temporary Retainer contracts).

StratCon Enhancements

Mapless Mode removes the Area of Operations map and plays like classic AtB - for players who want StratCon’s systems without the hex-based strategic layer.

Single Drop Mode generates one scenario per week scaled against your entire TO&E, rather than multiple scenarios across a map. The glossary explains why this works well for cooperative campaigns.

Official Challenge Scenarios pit you against a small, highly skilled and well-equipped OpFor in a duel scenario. The intent is that multiplayer groups split their players - some control BluFor, others take the OpFor. If these scenarios don’t fit your campaign style, delete them from the Briefing Room and use the new “Add a StratCon Scenario” button to generate something else.

Both Mapless and Single Drop modes are designed with streamers and large multiplayer campaigns in mind. Important: Don’t enable these modes mid-contract. Start fresh.

Veterancy Awards Return

When a character reaches Veteran rank, they now receive a free Special Pilot Ability. However, there’s a small chance (2%) they’ll receive a Flaw instead - and some of those flaws can be career-ending or severely debilitating.

This reflects our design philosophy: free power comes with risk. One character might get Natural Aptitude/Gunnery; another might get Combat Paralysis. Such is the cost of spinning the wheel.

Additional Features

Handheld Weapons & Lift Hoists: Full MekHQ integration for both systems. These can now be maintained, assigned, and tracked through your campaign. Princess doesn’t understand handheld weapons yet, but your players can use them freely.

Unit Market Expansion: The Unit Market now includes Support Vehicles, DropShips, JumpShips, Infantry, and Battle Armor.

Seven New Contract Types: Updated contract type generation provides better variety.

Family Tree Viewer: Track generational campaigns more easily by viewing a character’s complete family tree.

Diplomacy Report: A new report in the Command Center shows faction standings and diplomatic relationships at a glance.

Mid-Campaign Feature Enablement

Many new features now include “Options Changed” dialogs that help existing campaigns adopt new systems without starting from scratch. When you enable features like CamOps Salvage, Prisoner Capacity, Advanced Scouting, MASH Theater tracking, or Veterancy Awards mid-campaign, you’ll receive appropriate free units, personnel, or skills. This applies to bug fixes as well - turning Advanced Scouting or Prisoner Capacity back on after this release will grant the resources needed to use the updated systems.

Quality of Life Improvements

Deployment: Deploying from the TO&E or Briefing Room (right-click on scenario) is now available. Force remember their assigned Combat Roles, and a new “Cadre” Combat Role distinguishes between forces training allies versus your own personnel.

Daily Report: Now supports tabs for filtering and organizing information.

Glossary: Significantly expanded with new entries and tutorial documentation throughout the program.

Personnel & Units: Quick Train system speeds up personnel development. TO&E assignments can be managed directly from the Hangar. Auto-mothball prompts appear when beginning transit. MegaMek client settings are accessible from within MekHQ.

Logistics: Transportation costs overhauled to align with Campaign Operations. Maintenance schedules now self-correct. Parts in Use correctly tracks biped vs. quadruped ‘Mech components. Conventional infantry can now be refit.

Critical Bug Fixes

• Advanced Scouting: Fixed and ready to use
• Prisoner Capacity: Fixed and ready to use
• Battle Armor Skills: Now use the correct skill
• Pirate Campaigns: Recruitment works properly for low-reputation campaigns
• Prisoners of War: No longer incorrectly display as Camp Followers
• Morale System: Now works as intended

Campaign Options Updates

• FM:MR Unit Reputation option removed (Campaign Operations is now the standard)
• New option to restrict soldiers to small arms only
• Option to disable seed forces in StratCon
• Option to prevent tornadoes in scenarios
• Option to obstruct parts/unit delivery while in transit
• “Only Commanders Matter” option for multi-crew vehicles

Community Growth

We’re excited to share that our Discord server has crossed 5,000 members! This is a remarkable milestone for our community - for context, we had around 700 members back when we were on Slack. Thank you to everyone who has joined and contributed to making this such a welcoming place for BattleTech enthusiasts.

MekBay

MekBay has launched! If you haven’t checked it out yet, head over to mekbay.com. Drake and cat/dev/random continue to do phenomenal work pushing out updates to improve functionality.

Unlike the core programs, MekBay releases updates continuously—you’ll see a notification when updates are available and can update immediately. If you’re a web developer interested in contributing, the code is available for review and contribution.

Technical Stuff

Java 17 is Required for all 0.50.x Releases

Starting with version 0.50.0, Java 17 is REQUIRED to play. We’ve updated our guide to Updating to Adoptium (Eclipse Temurin Open Source Java) with detailed instructions.

It’s crucial to read the directions carefully, especially Step 6, which covers a recent change to the Adoptium installer. Make sure to select “Install for all users of this machine” in the Installation Scope.

We will continue using Java 17 until Fall 2026. If you choose to use a Java version beyond 17, it isn’t officially supported, and our standard response for issues will be to revert to Java 17.

WARNING: Java 24 was released (18 March 2025)! MegaMek still only requires Java 17, but if you are running on an older 32-bit OS, DO NOT INSTALL JAVA 24 as it has officially dropped support for 32-bit Windows.

Important: MekHQ Campaign Update Instructions

It is critical to follow these steps to ensure the integrity of your MekHQ campaign when updating between versions. Failure to follow these steps can result in the corruption of your campaign file.

Treat each release as stand-alone; Copy, never Move your data forward from older versions. MekHQ is NOT backward compatible.

1. Make a backup of your campaign and custom files. This is a critical step to prevent data loss!
2. DO NOT COPY MegaMek saves or any preference file from a different version to avoid compatibility issues.
3. Update MekHQ to the latest version. NEVER overwrite the existing folder; always keep each version in its own folder.
4. Re-save any custom presets to ensure they are updated with the new version’s settings.

A Few Reminders

The Milestone System Summary

Please see this link for details on our Milestone release system.

State of the Universe & Development Updates

If you haven’t read our recent posts, we recommend checking out:

• 2025 State of the Universe
• Looking Ahead and Looking Back: MegaMek Development Update 2025

User Data Directory

We have a customizable User Data Directory feature that allows you to set a single external directory for storing game resources like units, camos, and fonts, accessible across different installations and versions.

Set up this directory via client settings. A game restart is required for changes to take effect.

Social Media

Join our official MegaMek Discord, our primary community hub for the suite. We offer voice support, individual channels, and assistance for the official public servers. We’re also part of community Discords Everything BattleTech and Classic BattleTech. Find us on Facebook at MegaMek BattleTech and MegaMek.

Contributing

Interested in contributing? Find out how here.

Change Logs (Release Specific) and Download Links

MegaMek Change Log

Full Changelog: View on GitHub
Download MegaMek 0.50.10

MegaMekLab Change Log

Full Changelog: View on GitHub
Download MegaMekLab 0.50.10

MekHQ Change Log

Full Changelog: View on GitHub
Download MekHQ 0.50.10

by Hammer

If you’ve been with the project a while, you likely remember long nights spent playing Against the Bot—or AtB—our community’s single-player campaign system for MekHQ. Originally a fan-made spreadsheet, it was integrated into MekHQ by Neoancient in 2014, becoming the Digital GM behind countless memorable campaigns. Over time, StratCon expanded on those ideas with a strategic map and improved systems. As StratCon grew, AtB’s aging code became harder to maintain, limiting both development and player experience. We kept it running as long as possible, but it’s finally time to let it rest. This post celebrates AtB’s legacy and explains why it’s being retired.

The Origins of AtB

Before MekHQ even existed, BattleTech players were creating homemade campaign systems for MegaMek. They wanted persistent forces, ongoing stories, and characters who survived—or didn’t—between battles. That desire became Against the Bot, a spreadsheet created by early community members like Makinus and Snimm, later refined by scJazz and others lost to time. Players rolled for contracts, managed personnel, and generated opposition by hand—tedious, but beloved.

Then came Taharqa, who built MekHQ to bring campaigns into software. In 2014, Neoancient took the next step—turning the AtB spreadsheet into integrated code. It was one of his first major MegaMek projects, and while he later admitted he’d design it differently today, it worked. What had been a spreadsheet became a living system.

Here are some legacy screenshots showing how far we’ve come

❮

❯

The Legacy

Once AtB arrived in MekHQ, everything changed. Campaigns had structure, persistence, and consequence. The player base grew dramatically, long before the release of Harebrained Schemes’ BattleTech, giving single-player BattleTech fans a digital GM and a way to tell their own tales. The result was staggering: hundreds of campaigns, thousands of battles, tens of thousands of destroyed ’Mechs—and countless memories.

As the community expanded, developers like Ralgith and Windchild carried the torch. Windchild’s work, which came later, deepened the human side of MekHQ—making personnel feel like real characters rather than statistics.

AtB’s influence reached beyond MekHQ. The demand for smarter opposition improved Princess. Refit mechanics and error reports drove progress in MegaMekLab, which in turn led to MekBay. Even now, many features trace their roots to requests from AtB campaigns.

Every contributor—coders, artists, data curators, and testers—volunteered their time for love of BattleTech and the community. A few names deserve special mention:

• Akjosch – First planetary rework, foundation for the campaign map.
• Arlith – Tireless rule implementation, endless bug hunting in MegaMek (many from AtB campaigns), and overall MegaMek stability.
• Beerockxs – Sustained MegaMek and MegaMekLab through key years.
• Bloodwolf – Relentless tester and artist, essential but often unsung.
• DarkISI – Managed data before 2013, keeping tabletop accuracy alive.

To all the developers and contributors who continue to support MegaMek, MegaMekLab, and MekHQ today—you know who you are. Your dedication and creativity keep these projects thriving. And to the next generation reading this and thinking you’d like to be part of this legacy—there’s always room to join, to learn, and to help carry it forward.

Their work built the foundation we stand on today.

Why Retire It

AtB’s integration was always meant to be permanent—it was baked deep into MekHQ’s systems. Contracts, opposition generation, even campaign logic all assume AtB is active. That tight coupling now prevents further progress. Every improvement risks breaking something tied to AtB’s old design.

The limitations of AtB were recognized early, and addressing them took considerable time and effort—eventually leading to the development of StratCon. In many ways, StratCon represents the natural evolution of AtB, building on its foundations while moving toward a more flexible and modern framework. Over time, StratCon became the primary way to play campaigns, offering systems that AtB could no longer sustain. Yet even as we gradually separated the two, AtB’s roots remained embedded in the core codebase, leaving us with technical debt that must now be resolved. And if we ever want to create something truly new—a campaign system built from scratch for the next era—we’ll still need to untangle these legacy systems first.

The biggest issue is balance. AtB was created when early bots like TestBot and Princess were simple and predictable. To stay challenging, AtB compensated by heavily outnumbering the player. But today’s Princess is far more capable. Those old assumptions now create unfair, frustrating battles. Fixing this would require rewriting the system from the ground up.

That’s why StratCon was built—to use modern balancing, scalable architecture, and adaptable systems that can grow with future improvements. As StratCon evolved and became the community standard, AtB’s relevance declined. Yet its deep integration left us bound to outdated design choices, slowing development and blocking key features like persistent enemies and advanced contract systems.

With the upcoming 0.50.10 release, AtB will be fully removed from MekHQ.

What’s Next

To ease the transition, we’re introducing StratCon Mapless Mode—a version of StratCon without the campaign map, but with all the improvements AtB never had: better OpFor generation, refined salvage and logistics, convoy and rescue missions, and more. Existing AtB campaigns will automatically migrate to Mapless Mode when loaded into 0.50.10, keeping your units, history, and stories intact.

Moving Forward

Removing AtB isn’t the end of single-player campaigns—it’s the removal of a barrier. By eliminating the accumulated technical debt, we can finally begin exploring what’s possible: discussing persistent OpFors, expanding contract systems, and developing new campaign mechanics. This doesn’t commit us to those features, but it opens the door to see where future development might lead.

For many, AtB’s retirement feels like losing an old comrade. It’s understandable—AtB has been part of MekHQ’s identity for over a decade. But its spirit lives on in StratCon, now stronger and more flexible than ever.

To the original spreadsheet pioneers: thank you. Your work shaped a generation of digital BattleTech campaigns. To those who’ve kept AtB alive for years: your dedication showed us what mattered most. And to every commander who ever fought against the bot: your stories endure.

Against the Bot served with honor. Now it’s time to retire its colors and march forward together.

Seyla!

Questions or concerns about StratCon Mapless Mode? Join us on Discord for support and discussion during the transition.

I can’t believe it’s been almost five months since our last MegaMek release. As we move into the next set of development releases, I wanted to take some time to discuss what’s been happening over these past five months. We’ve had some very significant changes, and while some of our previous blog posts have touched on these topics, I think it’s important to bring everything together in one place.

For more details on what’s been happening with the projects over the past several months, check out our Looking Ahead and Looking Back: MegaMek Development Update 2025 post.

The Big Picture: Licensing and Code Modernization

Probably the biggest change is that we are now officially operating under our new licensing structure. All of our code across all projects is now under GPL 3, and all of our data has been moved to Creative Commons. If you want to dive deep into the nitty-gritty of what changed, when we made these licensing changes, and why, check out our comprehensive licensing announcement from May. We’re glad to have this process completed and behind us.

Code Refactoring: The Necessary Overhaul

In addition to the licensing changes, we’ve had to make significant refactoring to our codebase across all three programs. If you’re not familiar with the term “refactoring,” think of it as pulling every single item out of a closet, organizing everything, and then putting it all back in a new, more logical order. It’s the same stuff, but structured better for future use.

What This Means for 0.50.07

A few important things to understand about this release:

This release is massive in terms of code changes. Every one of the programs has undergone extensive overhauls. The numbers speak for themselves:

• MekHQ: 419 pull requests merged
• MegaMek: 244 pull requests merged
• MegaMekLab: 97 pull requests merged
• Total Changes: 760 unique PRs across all three programs

For those unfamiliar with the term, a “pull request” (or PR) represents a single code change, bug fix, or feature that has been reviewed and merged into the program. Each PR can range from a simple one-line fix to massive overhauls involving hundreds of files. The 760 PRs in this release represent an enormous amount of work from our volunteer development team and contributors.

When you look at the changelog, it is literally too large to include in a single blog post. Instead, we’re going to highlight a few key improvements like we normally do and let you explore the full release notes at your own pace.

We do expect some bugs and issues. You cannot undertake this level of changes and refactoring without encountering some problems. This is the reality of software development, especially with a codebase that’s been evolving for 23 years. While there will be issues, we’ll work through and fix them as they’re reported. The key point is this: in the long run, these changes put us in a much better position code-wise than we were before.

A Massive Thank You

I need to call out and thank Tex for taking on the absolute Herculean job of leading much of this code refactoring work. Additionally, I want to recognize all the other developers for helping, chipping in, supporting, and doing everything they do to make these programs what they are. This was truly a team effort, and the amount of volunteer hours that went into this release is staggering.

Looking Ahead: Release Timeline and Java Support

We’re looking forward to being in open waters for a while. As we look further ahead, we don’t anticipate another Milestone release until probably well into 2026. As we approach the end of 2026, we will also be upgrading our Java requirements, as we’ve discussed in previous announcements.

Current Java Support Status

Let me clarify our current Java position:

Right now, we officially support only Java 17. This is what we test and code with, and this is what we recommend all players use.

We do have community members using Java 21, and knock on wood, they aren’t reporting any significant issues. However, that doesn’t mean we’re officially telling you to upgrade to Java 21. We are actively evaluating what the next upgrade path will be, and we’ll communicate that decision well in advance when we make it.

If you experience any issues while running on Java 21, our first troubleshooting step will be to ask you to revert to Java 17 to see if the problem persists. That said, if you are using Java 21 and have any feedback—positive or negative—please let us know.

MekBay Update: For Those Who Missed the Launch

In addition to all the changes in the core programs, we’ve been steadily developing MekBay. If you missed the announcement or haven’t checked it out yet, I encourage you to read Introducing MekBay. Drake and cat/dev/random continue to do phenomenal work, steadily pushing out update after update to improve the functionality. We have really big plans for this tool’s future.

MekBay’s Different Release Model

Something important I want to call out: MekBay will not have releases like MegaMek. MekBay will release updates continuously. If you’re using MekBay, you’ll simply see a notification when updates are available, and you can update immediately. It’s much more like a modern web application in that respect.

To head off the inevitable question: “Why can’t you do that for the core programs?”

The simple reason is we can’t. The nature of the code in the original programs (MegaMek, MegaMekLab, and MekHQ) prohibits that kind of automated updating system. These programs were built in an era before such systems were common, and the architecture doesn’t support patching or automated updates. It’s just not feasible for us to even remotely consider any type of patching or automated update system for the core programs without a complete rewrite.

MekBay’s Future Integration

We’re really looking forward to expanding what MekBay can do and how it aligns with MegaMek. In particular, we’re exploring ways to build units and create unit lists that can be seamlessly passed back and forth between the programs. However, this is not something that’s going to be built overnight. We need to be realistic about our resources and the fact that we currently have the capacity to support both programs, but development on integration features will take time.

If you are a web developer and are interested in contributing to MekBay’s development, the code is available for review and contribution. We’d love to have more hands helping with this exciting new tool.

BattleTech Playtest Rules

We’ve implemented Playtest Package One and Playtest Package Two in this release as optional rules. If you’d like to try them out, you can enable them in the game options by searching for “PlayTest.” For complete details on our approach to the playtest rules, backwards compatibility, and what this means for MegaMek’s future, please read our comprehensive playtest implementation announcement.

What’s New in This Release

With all that context out of the way, let’s get into some of the new and exciting features in 0.50.07!

MegaMek

MegaMek has received substantial updates across gameplay, UI, and core systems:

New Rules & Features

• Booby Trap rules for ground combat
• Heroic/Legendary skill level tracking
• Public Playtest 1 and 2 Implementation
• Favorite bot behavior and new convoy AI options
• Enhanced multiple map and odd-width map support

Faction & Unit Updates

• Faction data overhaul: new factions, updated Clan forces, improved availability
• Many fixes to Battle Armor, ProtoMek, trailers, equipment rules, BV calculations, ammo handling, and weapon effects

UI & Gameplay Improvements

• MekView Entity Readout updates with improved display
• New keybind options, zoom controls, and phase report layout
• Better quick tips, new splash screen for ultrawide monitors, onboard PDF viewing
• Board editor upgrades: deployment zones, board tags, advanced search

Bug Fixes

• Mobility/PSR improvements and consistent building entry for infantry
• Numerous NPE (Null Pointer Exception) protections for movement, lobby, and targeting
• UI and icon fixes for units and faction/tech details
• Improved force assignment, chat, and starting location in the lobby

Behind the Scenes

• Faster, more robust build and logging systems
• Refactored panels/dialogs for smoother performance
• Updated Gradle, dependencies, and internal code organization

MegaMekLab

MegaMekLab has seen substantial improvements to record sheets, GUI usability, and construction options:

Record Sheet Improvements

• Fancy pips for better visual clarity
• OmniVees now properly display as Omni on the sheet
• Physical attacks now displayed on record sheets
• To-hit modifiers added (with ongoing work for obscure cases like interface cockpits)
• Default font changed to Roboto for cleaner, more readable sheets
• Max Heat (Dissipation) calculation improved, now handles rapid-fire and one-shot weapons correctly
• Various handheld weapon fixes, mostly related to ammo display
• PPC Capacitor now correctly adds Clan CASE to the location
• Beast-mounted infantry now use the correct damage divisor
• Shields display the correct number of pips again

GUI Enhancements

• Sort units in the print queue
• Reworked Conventional Infantry UI is cleaner and less error-prone
• Battle Armor ammo bin size can now be set from the Equipment tab instead of requiring the Criticals tab
• Items weighing less than a kilogram now display their actual weight instead of 0 (particularly relevant for some conventional infantry weapons)
• Better layout for quirks selection

Construction Options

• Modular Weapon Mount for Battle Armor added
• ProtoMek Transport Bays (on DropShips and similar) now functional
• Gun Emplacements construction support! (These DO NOT support official rules, only emplacements as we have implemented them)

MekHQ

MekHQ has received extensive updates this release, with improvements touching nearly every aspect of campaign management. Here are some of the highlights:

Personnel & Character Systems

• Introduction of a brand new personnel recruitment market
• Attribute scores now impact skills
• Heroic & Legendary skill levels are now tracked
• Numerous new SPAs added, including some specifically for Administrators
• Added 254 Civilian Professions
• Admins can no longer take multiple admin professions at the same time
• Added the ability to perform single-attribute and double-attribute AToW attribute checks
• Permanent AsTechs & Medics now have tangible value

Faction & Reputation Systems

• Introduction of a brand new faction reputation tracking system
• New campaign starting locations - no more starting on Galatea with every campaign
• New options for randomized campaign factions & start dates

StratCon & Combat

• StratCon now supports pirate campaigns, me harties!
• OpFor callsign generation can be toggled on/off
• Stopped the Clans cheating at Batchalls (yet again) and other critical force generation fixes
• Decreased support point cost of Mercenary Auctions & Ronin Hires by 50%
• New, more accurate tracking of contract requirements

Interface & Quality of Life

• General GUI improvements across the main interface and many smaller dialogs
• Significant improvements to Mass Repair and Mass Salvage
• Massive glossary updates with a new look, new entries, and documentation now viewable in-game!

Plus over 100 other bug fixes & improvements not individually listed here.

• Nearly forgot…Rather raid than trade? Hoist the Jolly Roger, take what you can salvage, and owe nothing to the Great Houses, me harties—MekHQ now supports pirate campaigns!

Important: MekHQ Campaign Update Instructions for 0.50.07

Over the past year, we’ve become aware that upgrading campaigns across versions has become increasingly tedious, with more steps added each release. You had to resave your campaign, manually open and close MekHQ, end current contracts, etc. That’s why, in 0.50.07, we’ve added an automatic campaign upgrader to MekHQ. Simply load your 0.50.06 campaign and follow the instructions on screen. MekHQ will handle everything.

Before You Upgrade:

• Save your campaign in 0.50.06. Since 0.50.06 was a Milestone release, this is required for 0.50.07 to load your campaign.
• Save any custom presets in 0.50.06. Presets not saved in 0.50.06 will not be compatible with 0.50.07.

Safety Steps:

1. Make a backup of your campaign and custom files. This is critical to prevent data loss.
2. Keep each version in its own folder. Never overwrite existing installations - MekHQ is NOT backward compatible.
3. Do NOT copy MegaMek saves or preference files between versions.

Once you’ve completed these steps, load your campaign in 0.50.07 and follow the on-screen prompts. The automatic upgrader handles the rest!

Technical Stuff

Java 17 is Required for all 0.50.x Releases

Starting with version 0.50.0, Java 17 is REQUIRED to play. We’ve updated our guide to Updating to Adoptium (Eclipse Temurin Open Source Java) with detailed instructions.

It’s crucial to read the directions carefully, especially Step 6, which covers a recent change to the Adoptium installer. Make sure to select “Install for all users of this machine” in the Installation Scope.

We will continue using Java 17 as our official supported version through 2026. If you choose to use a Java version beyond 17, it isn’t officially supported, and our standard troubleshooting response will be to ask you to revert to Java 17.

A Few Reminders

The Milestone System Summary

Please see this link for details on our Milestone release system.

User Data Directory

We support a customizable User Data Directory feature. This allows you to set a single external directory for storing game resources like units, camos, and fonts, which is accessible across different installations and versions of MegaMek, MegaMekLab, and MekHQ.

For complete details on setting up and using the User Data Directory, see our previous release notes or the documentation in the programs.

Social Media

Join our official MegaMek Discord, our primary community hub for the suite. We offer superior voice support, individual channels, and assistance for the official public servers. We’re also part of community Discords Everything BattleTech and Classic BattleTech. Find us on Facebook at MegaMek BattleTech and MegaMek.

Contributing

Interested in contributing? Find out how here.

Change Logs (Release Specific) and Download Links

MegaMek Change Log

Full Changelog: View on GitHub
Download MegaMek 0.50.07

MegaMekLab Change Log

Full Changelog: View on GitHub
Download MegaMekLab 0.50.07

MekHQ Change Log

Full Changelog: View on GitHub
Download MekHQ 0.50.07

Thank you for your continued support and patience as we work to improve these programs. We’re excited about where the project is heading and grateful to have such a dedicated community along for the journey.

Seyla!

By Hammer

As a lot of you know, MegaMek has been around since 2002. And since its inception, we have introduced MegaMekLab and MekHQ, which have become incredibly successful parts of the MegaMek suite. All of our projects have always been built in Java, but we’ve watched in the last few years as things have moved online, more cloud-based. We consistently hear two big requests from the community: a web-based way to play MegaMek, and having a web-based tool for searching units, building forces, and then generating record sheets. MekBay addresses the second request as our first move into web-based tools, and represents our first full project that’s not Java.

Click images to view full size

MekBay represents our fourth official project and a significant milestone in the evolution of the MegaMek suite. We want MekBay to evolve the same way MegaMek has with community feedback, developers, and contributors who want to bring the love of the BattleTech Universe to their friends and families. While MegaMek represents (in our opinion) the best way to play an electronic representation of BattleTech we want MekBay to support TableTop in a way the MegaMek, MegaMekLab, and MekHQ can’t. For years, you’ve asked for mobile access, web-based tools, and the ability to manage your BattleTech games without being tied to a desktop. We hope MekBay will start to deliver on those wishes. But now for some details on what it does today.

Current Features

Complete MML Unit Database

Access the full MegaMek unit database directly from your browser or mobile device. Every unit that MegaMek can build and print is available with complete technical specifications.

Force Builder with Cloud Saving

Build and manage your forces with automatic cloud synchronization. Start building on your desktop, continue on your phone, and finalize on your tablet-all seamlessly synced.

Printable Record Sheets

Generate clean, printable record sheets for tabletop play.

• Note: there is a known issue with iOS devices where record sheets may split across pages due to automatic footer insertion by Safari and other iOS browsers. We’re investigating workarounds for this Apple platform limitation.

Important: MekBay IS NOT a canon source - these are functional game sheets designed for practical use, not official publication materials. As some of you know, MegaMekLab helps produce record sheets for official BattleTech products. When official record sheets are available through Catalyst Game Labs’ products, those will always be considered the official sheets.

Key differences from official sheets:

• Font styling: Different fonts used for optimal mobile display
• Unit name formatting: Bold unit names for better readability
• Heat scale display: Uses arrows instead of asterisks on heat scales
• Equipment inventory: Each equipment piece listed on separate lines without quantity columns for cleaner mobile viewing
• Hit modifier tables: Includes hit modifier tables adjacent to inventory sections
• Visual elements: Focuses on hit tables and functional gameplay elements

Advanced Search Engine

Powerful filtering capabilities let you search by unit type, statistics, factions, eras, and equipment using logical operators. Find exactly the units you need for your scenario or campaign.

Interactive Unit Sheets

View and interact with unit data in an intuitive interface designed for quick reference during gameplay.

TRO Browser

Browse through units in a MechWarrior-style interface, complete with improved UI elements and bug fixes from community feedback.

Technical Implementation:

• Built as a Progressive Web App with an Angular frontend (TypeScript, CSS, HTML) and NodeJS backend (JavaScript + MongoDB) for Cloud Sync when online
• Delivers a web-based experience that works offline after initial load
• You can save it as an app on your phone or tablet, making BattleTech unit management truly portable
• Your data syncs across all devices (with real-time sync planned for future releases)
• All unit data, factions, eras, quirks, and equipment pull from MegaMek’s databases with automatic updates when online

Currently using static SVG exports from MegaMekLab for record sheets, with plans for dynamic sheet generation in future versions.

Future Roadmap

As we continue developing MekBay, several exciting features are planned for upcoming releases:

Real-Time Sync

Multi-device real-time synchronization ensures your sheets stay current whether you’re using your phone, tablet, or desktop browser-an upgrade from the current cloud sync system.

Multiplayer Read-Only Sheets

Share unit sheets with opponents in read-only mode, allowing them to view your units while maintaining data integrity through real-time sync.

Unit Construction

Full unit construction capabilities with complete MegaMek compatibility. Units built in MekBay will work seamlessly with MegaMekLab and vice versa.

Enhanced File Format Support

Expanded support for MUL and other file formats to ensure maximum compatibility with the MegaMek suite of programs.

Built in GATOR Calculator

In development a built-in GATOR calculator that will tell you odds.

Beta Status and Community Involvement

MekBay is currently in beta at https://mekbay.com with ongoing development. As with all MegaMek projects, we’re committed to community-driven development and welcome your feedback.

A note for people wanting to contribute to MekBay. We’ll need your feedback to make it everything it can be. The code for MekBay will soon be in our repositories. In the past we’ve had people that have wanted to contribute to the projects but haven’t wanted to work in a Java environment. If you’re a web developer, have a look at MekBay. And if you want to help out, we’d love to hear from you on our discord.gg/megamek

Feedback Channels: All feedback should be directed through our established MegaMek channels:

• Discord: Join our community at discord.gg/megamek
• Coming Soon GitHub Repository and Trackers:

Looking Forward

Whether you’re a veteran commander who’s been with us since 2002 or a new recruit discovering the Inner Sphere, MekBay opens new possibilities for how you engage with BattleTech. We’re excited to see how you use these tools to enhance your tabletop campaigns.

As an official MegaMek project, MekBay will receive ongoing development support and continue evolving based on community needs and feedback. This represents our commitment to making BattleTech more accessible to players regardless of their platform or technical setup. By expanding beyond our traditional Java environment, we’re opening doors to new possibilities while still staying true to the MegaMek experience.

Join us and help us build the future of portable BattleTech tools.

The next evolution of the MegaMek suite begins with MekBay, we want the evolution to be mobile.

Seyla!

Visit https://mekbay.com to try the beta now, and join our Discord at discord.gg/megamek for the latest updates on all our developments.

MegaMek’s Implementation and Community Guidelines

By Hammer

We’ve been getting questions about how MegaMek will handle the new BattleTech playtest rules. Here’s our comprehensive update on what we’ve implemented and what you need to know.

Our Approach:

Our original position was straightforward: we couldn’t make decisions until we had rules in hand. Well, now we do. Our intention was always to implement new rules once we could see what they actually were. Now that we can see the rules and Catalyst’s playtest framework, we’re moving forward with implementation as optional rules.

**As of today, the code for Playtest Package One will be available and included in:

-The future 0.50.07-Development release

-Today’s nightly MegaMek build.**

Our commitment remains the same: MegaMek will always follow the most current official rule set, just as we’ve handled errata implementation in the past. However, we’re a volunteer, open-source project, so timelines for implementing major changes will vary based on developer availability.

Playtest Package One: Implementation Details

The rules are implemented quickly but accurately, following the playtest document as written.

What Are Nightlies?

Nightly builds are the bleeding edge of our development efforts, assembled nightly (around 2300 Eastern Time). These versions pack all the latest changes, offering a glimpse into the future of our software at the expense of stability. Expect the unexpected, as nightlies may occasionally break down in the heat of development.

Using Nightly Builds: Critical Information

Compatibility Requirements:

• Keep nightly builds in their own **SEPARATE FOLDERS from other versions
• ONLY USE the MegaMek nightly builds (DO NOT USE MekHQ integration - broken)
• Builds are only compatible with the EXACT SAME VERSION - i.e. September 11th and September 12th builds cannot play together
• You can only test against Princess (She doesn’t understand the changes) or with someone using your exact build version

Nightly Build Schedule: Nightly builds are generated at 3:00 AM UTC. Here’s when that translates to in your local time zone:

Note: Times for US time zones are for the previous day. India and Japan do not observe DST, so their times remain constant year-round.

Downloading Your Nightly Build:

1. Log into GitHub (You must have an account)
2. Navigate to the GitHub page of the MegaMek
3. Hit the Actions Tab
4. Look for the latest successful build, marked by a green checkmark (e.g., “Megamek Nightly CI #454: Scheduled”). Make a note of the build number for any potential issues
5. Scroll down to Artifacts at the bottom of the page, and select the non-Mac release for download

Enabling Playtest Rules: Playtest options are turned off by default. Enable them in Game Options > Basic Options > “Playtest Package One Survivability Rules” (about 3/4 down the list).

Enable Playtest Package One in Game Options > Basic Options - click image to view full size

The changes may be subtle - for example, ammo explosions will look different, but you’ll need to look closely to see the implemented modifications.

Example of Playtest Package One survivability changes in action - click image to view full size

Future Playtest Packages

While we have an excellent working relationship with Catalyst Game Labs, we’re fans who will likely receive future playtest rules when the general community does. We’ll implement them as quickly as possible into nightly releases, but several factors affect our timeline:

• Unknown complexity of future packages
• Unknown quantity of rules
• Implementation time requirements

This means we might implement rules after the playtest window closes. In other words we’ll do our test to get them out as soon as we can.

Important Limitations and Guidelines

Official Playtest Feedback: We’re an open-source, fan-based project. If you provide feedback to Catalyst stating your experience was based on MegaMek implementation, they may choose not to accept that feedback. We want complete transparency about this limitation.

Community Discussion: We’ve created a #battletech-playtest Discord channel for organized discussion. However, the MegaMek Discord is not monitored for official feedback. The development team cannot forward feedback to Catalyst, and we’re NOT implementing unofficial rules, spin-offs from playtest rules, or Discord commentary. We have a policy regarding unoffical or non-canon content

That said, if there’s a legitimate bug in our implementation versus how the playtest rules are written, an issue should be opened on the MegaMek tracker with the specific details.

Official Feedback: We strongly encourage testing rules on tabletop and providing feedback through the channels Catalyst has defined in their playtest documents.

Our Commitment Moving Forward

As developers, we’re excited to see BattleTech evolving. We’ll always endeavor to protect older rules as options where possible, but fair warning: there may be times when new rules or errata will override old ones, and we may have to remove older implementations depending on the scope of changes.

Until we see final rules and can evaluate their impact, we can only prepare and adapt. We’ll update everyone as we go.

For now, if you want to experiment with Playtest Package One, grab the latest nightly build, enable the playtest options, and give them a try. Remember all the compatibility limitations we’ve outlined.

Run those ammo bins dry and your PPCs hot!

For the latest updates join our Discord at discord.gg/megamek for community discussion in the #battletech-playtest channel.

MegaMek Development Update 2025

By Hammer

We’ve been relatively quiet these past few months as we’ve worked through licensing changes and repository restructuring. It’s time for a general update on where the projects stand and where they’re heading. This isn’t a full State of the Universe address—think of it more as a snapshot of where we are today and how we see things coming together for the foreseeable future.

An Incredible Year of Development

I’ll be honest: this year has been incredible. In the first seven months alone, we pushed an amazing amount of code with the largest number of developers and contributors we’ve ever had working on the project. We then started a code embargo at the beginning of summer to handle the repository updates and licensing changes across all files in all programs. Even with this necessary pause for restructuring, the output for the year has been unbelievable.

But like all open-source projects, change is constant. People come, people go. And as we look ahead, we’re seeing this natural evolution happening.

The Rest of 2025: Managing Expectations

As we look toward year’s end, we’re experiencing some transitions. Some developers have left, others have needed to slow down, and some contributors have gone quiet. This is normal—the project has thrived for 23 years and will continue, though the pace is likely shifting again to a slower tempo.

The licensing and restructuring changes are taking much longer than anticipated, which will impact our release schedule for the rest of the year. We released the 0.50.06-MILESTONE, and I’ll be honest with the community: it just barely meets our milestone standards. But we absolutely needed a milestone to push forward with everything required for the coming years.

About Version 0.50.07-Development

Many of you have asked about 0.50.07-Development’s release date. Let me be transparent: it will likely be a buggy development release. The volume of code refactoring we’ve done over the past two months to align with licensing changes will inevitably introduce bugs.

We originally hoped to drop 0.50.07-Development at the end of August, but the restructuring is taking longer than anticipated—we were overly optimistic. As of today, we’re looking at:

• Two to three more weeks of code restructuring
• A couple weeks of testing

Best case scenario: 0.50.07-Development releases end of September. Realistically: mid-October is more likely.

I know this is a long gap between releases, and we’re warning you it may be buggy. But we hope players understand that while this causes short-term frustration, it will greatly benefit the project long-term.

Project-Wide Updates

New Development Team Addition

We’ve moved long-time contributor Dgorsman to the development team. They’re diligently updating force generator files that drive OpFor creation across all three programs. These modernized files already produce more interesting forces and bring our data to the ilClan era. This is a major positive development that will benefit MegaMek battles, MegaMekLab unit availability, and MekHQ campaign play.

With Dgorsman moving to the development team, I’ll be stepping back from managing and handling the data aspect of the projects. I’ll still dabble, but the majority of data work will now go through them. Over the last few years, my role has evolved to be more of a community liaison and project lead. While I wear this second title with great humility as I’m not a coder, as one of the longest-serving members of the development team, I’ve become something like General Kerensky before the Exodus—the old soldier who’s seen every battle, trying to hold the Star League together while knowing when to make the hard calls. Sometimes leadership means rallying everyone behind a vision, and sometimes it means saying “No, we’re not implementing that feature, it would tear the codebase apart.”

Project Infrastructure Updates

Licensing Changes

We’ve completed the necessary communication period for contributors to decide whether they want their content included under the new licensing structure. I’m happy to report that through our outreach and community response, we’ve maintained everything except a few tilesets. For full details on the licensing changes, see our comprehensive announcement from May.

Our community survey revealed that the tilesets we need to remove aren’t widely used—they’re older sets, and most players are comfortable with the default Saxarba tileset. The following will be removed:

• Atmospheric
• BW_Atmosphere
• HQ_Atmospheric

Since we couldn’t secure permission, these won’t be available even as optional downloads. If you want to keep using them, I recommend backing them up from 0.50.06-MILESTONE. What you do with your personal backups is your choice, but we cannot include them in future packaging.

XML to YAML: Modernizing Data Management

For years, our data has lived in XML files—easy to package at the time, but increasingly problematic. As more players edit XMLs without understanding the structure, bugs and crashes result. While XML isn’t particularly hard, its formatting requirements can obscure the actual data.

We’re systematically moving all data to YAML files—each planet gets its own file. Eventually, house units (like the Davion Heavy Guards) will have individual YAML files. This format makes it easier for players to contribute and modify data like system ownership. It also provides a clearer structure for managing factions down to individual military units.

This will take a few years to complete, but we’re well underway. The bad news: players with customized XML files will need to handle conversions themselves, as we lack the resources to provide conversion tools. While I know AI tools are controversial to some, ChatGPT, Co-Pilot, Claude.ai, and Gemini have all been successfully tested for XML-to-YAML conversions. However, we’re not prepared to provide specific instructions for using these tools—our limited development resources must stay focused on our own conversions and code.

MegaMek Updates

In The Coming Release (0.50.07-Development)

We’ve added a new Tip of the Day system, which helps both new and experienced players discover features they might have missed. These tips now support HTML formatting, making them more visually appealing and informative.

Tool Tip demonstration - click play to start

We’ve also significantly expanded keyboard shortcuts throughout the game, adding keybinds for game commands, deployment phase actions, and phase report navigation. You can now even remove specific keybinds by pressing Esc, giving you full control over your setup.

Visual improvements include better Force Display functionality, enhanced Phase Report layout with keyword filtering, and improved zoom controls that let you zoom toward your mouse cursor or toggle between zoom levels with keyboard shortcuts. The Board Editor gets Deployment Zone painting capabilities, while the overall interface benefits from ultrawide monitor support for splash screens and various UI refinements.

For the data enthusiasts, we’ve done considerable rework on the Mech View and added a new Faction Availability tab that shows our interpretation of unit availability data. While our underlying data uses the Master Unit List, this represents our own analysis and interpretation of that information, making unit selection more historically accurate.

Click images to view full size

CASPAR/ACAR/PACAR: A Pause in Development

This update saddens me. We started with great optimism about creating CASPAR, but creating a new AI from scratch is no easy task—just look at any game ever made to see that AI is typically the biggest challenge. We’re fortunate that Princess, while occasionally sociopathic, works well for our needs.

We’re pausing CASPAR development for several reasons. The primary developer for CASPAR, ACAR, and PACAR has left the projects. We don’t know when or if they’ll return, and we lack the resources to continue expanding these systems. We’ll maintain Princess logs in case we can resurrect CASPAR, but for now, we consider this time well spent exploring alternatives. The work even led to some improvements to Princess along the way.

ACAR and PACAR will remain in the program and stay functional, but further improvements are unlikely, and bugs may remain open for a while. It was a unique concept that really needs their original developer to handle properly. We hope they’ll return, but we must plan as if they won’t.

Handheld Weapons: Awaiting Implementation

You may have noticed we’ve added handheld weapon construction to MegaMekLab. While the construction side is complete, implementing playability in MegaMek requires additional work.

The developer handling this feature needed time away but is returning to tackle the gameplay implementation. Like FrankenMeks, we suspect we’ll need rules clarifications from the game designers to ensure these weapons work correctly in actual play.

We’re committed to making these weapons fully functional in both programs—buildable in MegaMekLab and playable in MegaMek. Until then, they remain construction-only. We have no ETA, but this will be an exciting addition once complete.

Fluff Pack: A Moving Target

This passion project of mine has been years in the making, and I take full ownership of not getting it across the finish line yet. The challenge isn’t just technical—it’s keeping pace with the ever-expanding BattleTech miniature line.

Every time new minis are released or existing ones are repainted, our target shifts. We need to carefully manage both the number and size of images to avoid bloating the programs, while ensuring we have the right images that align with current miniatures. Additionally, these images need to be properly integrated into our data structure, which is simultaneously converting from XML to YAML.

Bottom line: we’ll keep working on it with no ETA, but it will come out if it’s the last thing I ever do.

MegaMekLab Updates

In The Coming Release (0.50.07-Development)

Construction Improvements

We’ve expanded construction options with Gun Emplacement support, allowing players to build these defensive structures directly in MegaMekLab using our own non-official construction rules. These units will function in MegaMek gameplay. Infantry construction has received substantial updates to both the GUI and underlying code, making infantry unit design more intuitive and accurate.

Record Sheet Enhancements

Record sheet generation has seen major improvements with new options for hit modifier columns and physical attack information. We’ve added Roboto fonts for better text rendering and made physical attacks optional for cleaner sheets when not needed. Handheld Weapon (HHW) record sheets now properly handle ammo counts, one-shot weapons, and cluster charts. The system also provides increased precision for sub-kilogram weight displays, essential for detailed Battle Armor and equipment calculations.

User Experience Updates

The Tip of the Day system helps both new and experienced users discover MegaMekLab’s extensive features. Quirks organization has been improved with better sorting and layout using a vertical grid system. The unit selector has been refined to prevent errors and improve navigation, while Battle Armor ammo bin sizing offers a more intuitive user experience.

FrankenMeks: Waiting for Clarity

Earlier this year, we discussed implementing FrankenMeks in MegaMekLab. While we’ve made some progress, we’re currently stuck waiting for rules clarifications from the game designers.

The core issue is that the ruleset for these units contains ambiguities. Humans can interpret and fill logic gaps when playing tabletop, but code requires precise rules. Until we receive official clarifications on construction logic and gameplay mechanics, we cannot properly implement these units in either MegaMek or MegaMekLab.

We’ve committed to making anything buildable in MegaMekLab also playable in MegaMek—no more construction-only frustration. Therefore, FrankenMeks remain on hold until we get the answers we need to implement them correctly in both programs.

MekHQ Updates

In The Coming Release (0.50.07-Development)

Personnel Market Overhaul

We’ve completely revamped the Personnel Market system, transforming recruitment from a routine task into a strategic challenge that reflects BattleTech’s gritty realism.

The new system replaces daily recruitment with monthly rolls, where your success depends on location, faction standing, and unit reputation. Three market types offer different experiences: the fully immersive MekHQ Market (location-based with hiring halls and population factors), CamOps Revised (official rules with added professions), and CamOps Strict (pure rulebook implementation).

Key improvements include:

• Strategic Planning Required: Travel to populated worlds with hiring halls for better recruitment odds
• Reputation-Based Quality: Elite recruits won’t join green units—earn better personnel through battlefield success
• Golden Hello Option: Offer one year’s salary upfront to attract higher-quality candidates
• Dependent System: Untrained hopefuls appear monthly, perfect for units investing in education
• Faction-Aware Generation: Personnel types match your location, era, and local factions

The system ensures all necessary professions are available (no more missing Administrators) while preventing anachronisms like ProtoMek pilots appearing in 3025. With recruitment now tied to Campaign Ops Reputation, falling below -25 means only pirates and mercenaries will consider joining your unit.

Faction Standings: The Politics of War

We’ve implemented a comprehensive Faction Standings system that brings political consequences to your campaign decisions. This system is distinct from Force Reputation—while reputation measures your professional prestige, Faction Standing is about trust, loyalty, and politics.

Click image to view full size

Key features include:

• Regard System: Measured from -60 (hated) to +60 (beloved), your standing with each faction affects everything from contract availability to special rewards
• Accolades and Consequences: Earn rewards like cash bonuses, free ‘Mechs, or propaganda support when in favor; face fines, leadership purges, or even disbandment when you fall from grace
• Ultimatums: Major historical turning points where neutrality isn’t an option—the Amaris Coup, ComStar Schism, or FedCom Civil War force permanent campaign-altering choices
• Climate Regard: Faction attitudes shift based on historical events (e.g., the Draconis Combine hating mercenaries after the 4th Succession War)
• Piracy Success Index: Pirates use a separate system entirely, gaining PSI through successful raids while risking legal crackdowns

Changing sides or defecting carries real consequences—loyal crew may abandon you or die in transition, and your old faction will blacklist you permanently. The system evolves through eras, shifting oversight from the MRB to MRBC to Clan Sea Fox’s MBA, keeping your campaigns historically grounded.

Core Systems Update

StratCon: Feature Complete and Future Plans

StratCon has become the primary way to use MekHQ. Internally, we view it as feature complete. We don’t anticipate adding much more, though there may be refinements to surrounding systems and OpFor creation.

One upcoming change: we’ll continue decoupling Against the Bot from StratCon. When AtB was implemented years ago, MekHQ was in its infancy, and our implementation approach wasn’t ideal. Currently, StratCon, AtB, and plain MekHQ (the campaign management tool) are so intertwined that fixing or improving one often breaks another.

Once decoupled, we’ll eventually decommission Against the Bot, leaving StratCon and the MekHQ campaign management tool. I anticipate this happening within the coming year. On the surface, you’ll notice few changes—just the removal of some options.

For those asking why we can’t keep AtB: it’s simple. Keeping it means bug reports from players using a frustrating, outdated system. We’ve determined it’s better to retire it. This removes technical debt and allows us to tweak StratCon without worrying about impacts to multiple systems.

In Active Development

A Time of War: Character Development Reimagined

Something you may have seen discussed on Discord is our implementation of A Time of War character development for player units. This has always been planned, but I want to clarify what we’re building and set appropriate expectations.

We’re implementing a character creator based on AToW, mostly following the rules but with concessions made for MekHQ. Characters created with our system won’t be identical to those made manually following the AToW manuals—we’ve had to adapt certain mechanics like experience points to work within MekHQ’s framework. However, they’ll be close enough that a game master familiar with both systems can convert between them.

What’s coming first is the Life Path builder—the foundation for the upcoming Advanced Character Builder. By itself, the Life Path builder doesn’t create characters; it creates the templates and paths that the full character builder will use. Think of it as building the toolkit before building the tools.

This system will have full support for the user data directory, maintain our Milestone-to-Milestone compatibility promise (just like saves), and include a one-click resave option to upgrade all custom life paths across versions with minimal fuss. The character creator itself should be available later this year or early next. We won’t be adding Destiny support, but we will include the ability to randomly generate NPCs, expanding the character roster of player commands.

I have to share the developer’s closing thoughts on this system: “This whole system is unbelievably cool. And I don’t mean our implementation—we’re just standing on the shoulders of giants. The AToW writers have done a fantastic job of capturing the tone and feel of each faction. I’ve always liked AToW conceptually, but this project has given me a real respect for what they’ve accomplished.”

It’s our hope that bringing RPG elements into MekHQ—especially the character builder—will reinvigorate interest in AToW and add new depth to campaign play.

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Company Generator Rewrite

The current company generator in MekHQ was originally designed as a standalone feature for the 0.49.7 release. While it does use some of the MegaMek RAT Generator data, it’s quite limited compared to the robust force generation capabilities available through MegaMek’s built-in Force Generator tools. Currently, we can only generate basic Mech companies, but players have been consistently requesting the ability to create combined arms forces - something our current system simply can’t handle.

We’re designing a completely new generator for MekHQ that will leverage MegaMek’s powerful Force Generator systems. This rewrite will allow us to generate detailed, realistic combined arms commands with diverse unit compositions including vehicles, infantry, aerospace units, and more. If you haven’t explored MegaMek’s force generation capabilities yet, fire up MegaMek, go to “Create Random Army,” and check out the 4th tab - you’ll get a taste of the kind of forces you could generate in MekHQ! This project is currently in the design phase, so stay tuned for updates as development progresses.

Awaiting Resources

Planet Editor: Building the Foundation

As part of the planetary rework, we’ve introduced an alpha systems editor that will be a top priority once the developer returns. You can try the current alpha version here—but please note this is very much in development and may have bugs or incomplete features.

Players have long wanted the ability to create alternate universes or see their military victories reflected in the game world. The editor will enable dynamic gameplay where successful planetary assaults change system ownership, potentially triggering future contracts as opposing houses attempt to reclaim lost worlds. While it’s not true AI strategy—more of a simple card trick—it adds meaningful consequences and narrative continuity to campaigns.

We hope for progress this winter, but with the developer’s return uncertain, we can only confirm it remains a priority to complete when resources allow.

Story Arcs: The Long Road

Story Arcs has been in planning for years. We currently have one story arc—Lone Wolves—which works, though some of our MekHQ modernization has affected certain options.

The challenge with Story Arcs is creating them without proper tools. The original developer can only work on the projects a couple months per year. When they returned earlier this year and we reviewed community feedback, it became clear we need a planetary systems editor and further planetary system rework first, not a Story Arcs editor.

This initiated our move from monolithic XML files to a more nimble YAML format. While we’re committed to completing Story Arcs eventually, we face a chicken-and-egg problem: we need an editor that allows regular people to write story arcs, then we need creative, story-minded people to write them. Until we have that editor, Story Arcs will remain in its current format with development paused for the foreseeable future.

New Milestone Timeline

We recognize we’ll need a new milestone sooner rather than later. We don’t like talking specific dates, but 0.50.07-Development won’t be a milestone. Looking at our remaining time this year, 0.50.08-Development will likely be the last release of 2025, and probably won’t achieve milestone status either.

Depending on bug counts in these next releases, we could have a new milestone by Q1/Q2 2026 if we can effectively squash bugs. While it may seem counterintuitive, we encourage players to play through each release rather than waiting for milestones. More players mean we find, track, and kill bugs faster—which means quicker milestones.

Looking Ahead: Slow but Steady

Reading the above, you might think the projects aren’t in a good place—but that’s far from true. They’re in a very good place.

To borrow from my earlier Kerensky reference: I’ve been standing watch over this Star League for a long time, and what looks like crisis to new recruits is just another Tuesday in the Inner Sphere. Developers leaving? That’s happened before—we adapted. Features getting paused? We’ve weathered worse storms. The difference is that after 23 years, we know these cycles are normal. Sometimes you’re defending against a Clan invasion, sometimes you’re rebuilding during peacetime. Right now we’re in one of those “garrison duty between wars” phases—not exciting, but necessary for the long campaign ahead.

The code and licensing changes position us better for new coders to join and learn as contributors. The licensing protects IP holders and us, while opening doors for us to ask for fundraising for specific needs like art or infrastructure support when necessary. Let me be absolutely clear: MegaMek will always remain open source and free. We’re a fan project built on love for BattleTech, not a business venture. Any fundraising would be rare, specific, and transparent—think “we need $500 for server costs” or “help us commission a new tileset,” never “donate to support development.”

While the development team is smaller in the second half of 2025 than the first, this is normal ebb and flow. Think of the first six months like the Amaris Civil War and First and Second Succession Wars—high tempo, high pace, lots happening. Now we’re entering our version of the Third Succession War—a quieter period where big things still happen alongside many smaller improvements.

If you code, want to learn to code, or have a head for coding, we’re open source and welcoming to those who want to contribute—provided they adhere to our guidelines and have passion for the BattleTech universe. Don’t be afraid to visit Discord and ask.

And while I can’t say much more about it, we are working on something absolutely epic. It’s truly a first for the projects and something I never thought I’d see. It’ll be a game changer for BattleTech players. We’ll have more to say this fall.

Thanks for Reading

The journey continues, and we’re grateful you’re part of it. Every bug report, every contribution, every game played helps make MegaMek better for everyone.

Seyla!