Changelog 

The full, per-release changelog lives in the repository, in CHANGELOG.md, and follows Keep a Changelog and Semantic Versioning.

Release highlights 

Version	Highlights
4.1.x	Multi-site correctness: suggestions are scoped to the current site, the backend module is permission-scoped, cache invalidation is per site, and the Bootstrap Package integration became opt-in. TYPO3 14 support. Requires the migration wizards — see Upgrade.
4.0.0	TYPO3 13 support.
3.1	Unified qualityLevel setting, replacing the split minimumSimilarity / proximityThreshold configuration.
3.0.0	TF-IDF scoring, stemming and stop word handling through nlp_tools, language detection from the site configuration.
2.0.0	Scores moved from the cache to a dedicated database table, computed by a scheduler task.

Upgrading between any of these is covered in Upgrade.