I tried to update the agent from the web console but it was version 2.7 and I was advised to do it manually.
I simply ran the installation on one of the 3 servers (running 2012 r2) with outdated agents and everything went fine without a reboot.
However the last server is a domain controller and the in-place upgrade failed to start the service ("Verify if you have sufficient privileges to start system services").
I had to cancel the upgrade and it reverted to version 2.7 but it won't start due to logon failure.
I rebooted the server but that didn't help with the upgrade.
I uninstalled the existing 2.7 and rebooted but the upgrade fails the same way.
I noticed that on the 2 other servers there are now 2 local accounts (AnturisAgent and AnturisRestricted).
I added those 2 accounts to the local SecPol "Log on as a service" but the upgrade still fails.
Currently there's no agent installed on this DC and I need this fixed ASAP.
Customer support service by UserEcho