6.0.2 was installed and I just upgraded to 6.0.3.
Out of 13 agents, 12 seemed to upgrade without problem, but one did not. It was "disconnected": Agent has unregistered (will upgrade) and was stuck there for a day. I restarted the service and eventually rebooted, to no avail. I uninstalled and deleted everything but the conf directory, downloaded the installer and reinstall it in the same default directory, specifying only the agent.
it is now stuck seemingly in an endless upgrade loop
I stopped the service, deleted all the log files (one has more than 4Mb), restarted it and here are the log files