What happens if you clear the plugins directory on the client machine? I recall having this issue with a customer and I think that's how we resolved it. I have a powershell script that takes care of it.
I've often thought of creating an add-in that would force reloading of the add-ins. One day I'll get to it.
Yes, that is one of the many things I've tried. If I delete the files in the plugins folder and restart EPDM, the old version returns.
After a bit of digging I have verified that it is a replication issue. I found the actual store file (00000001.unk) in the archive director on the server, and found that it is not up-to-date. There modified date and file size do not match one from a good server. I have already copied and replaced this file on one of the servers and verified that it works. I can write a script to do this, brute force, but I’d prefer to find out why EPDM is not replicating it automatically.