You can read the full release notes here, but I'll highlight some important information here

Previously 2FA was enabled in a single step which made it easy to lock yourself out. This is now fixed by using a two-step process, where the secret is generated first, and then 2FA is enabled by entering a valid 2FA token. It also fixes the problem where 2FA can be disabled without passing any 2FA token. As part of this change, 2FA is disabled for all users. This allows users who are locked out to get into their account again.

This update is also the reason you've been logged out of the web UI. Apologies for any inconvenience. /u/raymonf will be compensated in the form of rice.