If you accidentally performed an inconsistent upgrade, check the recovery instructions.
Used in UI
Since TeamCity 2017.2 automatic update option is available.
When a new version of TeamCity is detected, the server displays the corresponding health item for system administrators.
Since TeamCity 2017.2, the The item points to the server's Administration | Updates page, where all the versions available for the update are listed. The page contains notes about licenses compatibility, the new version description and controls to perform the automatic upgrade if you want to use that instead of performing the manual updating procedure.