We are on K2 5.4 FP 11. The K2 management site was throwing an error that was fixed in FP 8 so we were baffled. Turns out that we had run a setup manager reconfigure after applying the FP to change some configuration parameters and did not re-apply the FP as per the documentation so the FP was essentially rolled back?!
The way I understand it, a FP does 2 things a) updates the K2 database b) updates binaries in the K2 Program Files folder on the app server. The former can be verified using this and the latter can be verified because the Setup Manager box has a label on the top right stating the Version and FP level.
Having said this, can someone explain why re-applying the FP is necessary after running a reconfigure? How exactly can the software magically revert to an older version just by running the (updated!) setup manager?