I recently upgraded to TFS 2017 Update 1 from TFS 2015 Update 3, I thought I could simply update my build agents the same way I had with others by running the "Update All Agents" option from the agents pool.
Boy was I wrong.
I ran the operation, no errors, no logs, nothing. The agents went back up to running. So, I just assumed everything was successful. I ran a few of my builds and they were all OK. It wasn't until some other user with another build started having issues until we found they didn't really update to the latest version.
Then I read deep in the bowls of the agent documentation that it only supports minor version updates of agents, and I need to reinstall all of them. I'm fine with that, but the problem is there was absolutely no feedback to let me know of this. I mean, I really had to read through the documentation, had to dig through GitHub repositories to find the versions of agents between TFS 2015 and 2017. This wasn't some simple thing that was easily documented.
The "Update All Agents" option should fail or report an error / warning in the UI if the agents cannot be updated to the latest version of the agent for any reason! Otherwise us TFS administrators who deal with updates once or twice a year have a 10 minute problem become a day long problem.
Icons not visible on TFS2017.1/RC2
TFS 2017.1 notification management ERROR
Cannot add TFS server group to Access Level
Licence Using at TFS 2017 Report