diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 0ee8c01..2537c1f 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.3.0"
+  ".": "0.4.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 47a6fc4..d389d95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## [0.4.0](https://github.com/datons/python-datons/compare/datons-v0.3.0...datons-v0.4.0) (2026-03-13)
+
+
+### Features
+
+* switch default DataFrame backend to Polars ([53bded5](https://github.com/datons/python-datons/commit/53bded5049d7169f76c26604b82a48b2838373b4))
+
 ## [0.3.0](https://github.com/datons/python-datons/compare/datons-v0.2.0...datons-v0.3.0) (2026-03-13)
 
 
diff --git a/pyproject.toml b/pyproject.toml
index bd451fe..99cca1b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "datons"
-version = "0.3.0"
+version = "0.4.0"
 description = "Python client for Datons data APIs"
 readme = "README.md"
 license = "MIT"