It's been a while since previous major release and it's been a year full of wonderful development time. We've made first steps into making TeamCity more scalable (separate note to process running builds load and cross-server projects popup), added DSL to configure TeamCity projects from Kotlin code stored in the repository, added more integrations including dedicated GitHub integration and many more.
If you license maintenance time covers today or you use professional edition - upgrade today! Don't forget to take backup before upgrading as there is no downgrade path.
It seems about time to retire this announcements-only stream - follow the news and release announcements in TeamCity official blog.