The version matrix is a set of stored records that characterize the current minimum version capability required by the API server to serve requests from the client. In this way, outdated versions of the CodeStream extensions can be forced to upgrade before servicing, and deprecated functionality can be safely phased out.

In theory, separate minimum version enforcement can be set on an individual basis for each extension type supported (VSCode, JetBrains, etc.). In practice, however, we have found that all extensions usually are maintained at exactly the same version.

NOTE: Previously, the version matrix was stored in mongo, but has now been changed to a json file in the API server repo: api_server/etc/version_matrix.json.

For each extension, these fields are maintained:

Currently, the version matrix is stored in a json file in the api server repo: api_server/etc/version_matrix.json. It looks like this:

{
	"_id" : ObjectId("5b8082701a3a5d2711f0fc57"),
	"clientType" : "VS Code",
	"currentRelease" : "7.4.1",
	"minimumPreferredRelease" : "7.3.0",
	"earliestSupportedRelease" : "7.0.0"
},
{
	"_id" : ObjectId("5d83a95d970e5f999a86139a"),
	"clientType" : "VS",
	"currentRelease" : "7.4.1",
	"minimumPreferredRelease" : "7.3.0",
	"earliestSupportedRelease" : "7.0.0"
},
{
	"_id" : ObjectId("5d83a966970e5f999a86139b"),
	"clientType" : "JetBrains",
	"currentRelease" : "7.4.1",
	"minimumPreferredRelease" : "7.3.0",
	"earliestSupportedRelease" : "7.0.0"
},
{
	"_id" : ObjectId("5d83a96c970e5f999a86139c"),
	"clientType" : "Atom",
	"currentRelease" : "7.4.1",
	"minimumPreferredRelease" : "7.3.0",
	"earliestSupportedRelease" : "7.0.0"
}

clientType refers to the extension type (IDE) for the record in question.

Incoming requests contain a header field (X-CS-Plugin-IDE) that announces the IDE the request is coming from, and another header field (X-CS-Plugin-Version) announcing the version of the extension running in the IDE. The plugin header field is used to match against clientType in the database, and the version header field is compared to the three version fields within. The API server returns a header field (X-CS-Version-Disposition) in the response that announced its disposition relative to the passed extension version. The API server also returns header fields the information obtained from the version matrix, as follows:

The value returned in the X-CS-Version-Disposition header is determined as follows:

If no version or no plugin header is passed in with the request, the request is honored, and the X-CS-Version-Disposition header is set to "unknown".

Otherwise, if the plugin type isn't recognized, the request is honored, and the X-CS-Version-Disposition header is set to "unknownIDE".

Otherwise, if the passed version is unrecognizable or can't be parsed, the request is honored, and the X-CS-Version-Disposition header is set to "unknownVersion".

Otherwise, if the passed version is less than earliestSupportedRelease, the request is rejected, with the X-CS-Version-Disposition header set to "incompatible".

Otherwise, if the passed version is less than minimumPreferredRelease, the request is honored, but the X-CS-Version-Disposition header is set to "deprecated".

Otherwise, if the passed version is less than earliestSupportedRelease, the request is honored, but the X-CS-Version-Disposition header is set to "outdated".

Otherwise, the request is honored, and the the X-CS-Version-Disposition header is set to "ok".