- When you choose a user (e. g. to add a reviewer) inactive accounts are not suggested anymore.
- If you use side-by-side diffs (why ever would you?!), their performance has been improved
- Quite a few bug fixes.
You can find the complete release notes for Gerrit 2.11.3 here.
As for Jenkins, I’ve updated it from 1.623 to 1.626 as well. Nothing spectacular there but some bug fixes in the backend mostly.
The full changelog can be found here.