Here is our first update after 9.1 release. It has several critical fixes for issues reproducing on some installations and generic bug fixes, including some security-related. Thank you all who reported issues with 9.1 release!
Check the full list of fixed issues in our tracker and consider upgrading soon.
As usual, bugfix updates do not change the data structure, so for 9.1 installations this is an easy update with ability to go back if necessary.