Some more info from Paul:

The last time I tried to update it did not import the backup file. Richard Saunders looked into this at the time but never came back with an answer - is he still with Hansa?

ERP Version 8.5.342962
Windows Version 10 or server 12
Both client server and standalone

The issue was identified when trying to move to Version 8.5.342962 from 8.5.2020/01/07 Build 85330533.

A TB file was created from 0533. Version 2962 was installed and when the TB file was loaded into a client it crashed during import and hung the program. It was also tried to install the TB file direct to a clean install of the server but this also did not run smoothly. It crashed out during loading. If the server service was started with the database at this point the service could not be shut down. It would hang and require a server reboot to clear. No clients could log into the server in this state and also when the program was run in single user mode it would not start correctly after the failed import.

The same TB file was then installed back into an existing client on the network and it loaded fine so this is the PC we still have running today. This would indicate that the TB file is good and that its just something that has happened between versions that means the TB file will not load. I think that is where you need to look.

That was the bug report I filed. Richard had got a developer to look at it and see if they could work out why it would not update. The time was allocated then I never heard anything back after that. I guess Richard has gone then!!

It would be handy if you could ask if this was identified and fixed before I try and update again?