The process to upgrade the client software by selecting "Reinstall" from the web interface doesn't always work. I've seen it happen quite often where if you select an Access session and hit "Reinstall", it doesn't seem to do anything, and then it might work later, perhaps after a reboot.
I was testing this, and tried to "reinstall" an old agent running 6.8.20124.6845 (the server is on 19.1.24050.7079), and instead of doing nothing, it knocked the Guest out of the session. I think the software on the Guest is being killed in preparation for the upgrade, but then the upgrade doesn't happen. If I reboot, the Guest joins the session again and the version is still 6.8.20124.6845.
If I manually install the new agent on the Guest, then it successfully upgrades it.
Customer support service by UserEcho