I have two Replication Appliances that are 18.104.22.168 Build 2207269 and I want to update them to 5.8.0. I have downloaded the upgrade ISO and changed the appropriate settings to update via CD-ROM. After hitting the Check Updates buttons the machine got stuck at Checking for available updates. Both the Check and Install Updates buttons are grayed out. The weirdest part is that after restarting the VM it still says Checking for updates. I have this happening in two different vCenters. Any help would be appreciated. Thanks.
Only a guess. Please take a look at vCenter Server Appliance checking for update hangs. Although related to the vCenter Server appliance, you may try to see whether this also works for the Replication Appliance.
I tried that out and had high hopes for it. Unfortunately it still didn't want to work for me, and seeing as how I do not have enough experience with Linux I could not make the offline repository. I ended up un-registering the appliance from vCenter and deploying the updated one.