The 9.2.1 release patches the 9.2.0 release with a fix for a TypeScript issue using vector layers.

List of all changes

See below for a complete list of features and fixes.

• Add test cases for typescript use (by @tschaub in https://github.com/openlayers/openlayers/pull/15834)
• Do not make the source type of a vector layer generic (by @ahocevar in https://github.com/openlayers/openlayers/pull/15831)