When I submit a unit file with the same name as one already in the registry, but where content differs, I get the following message:

$ fleetctl submit xxxx.service
WARNING: Job(xxxx.service) in Registry differs from local Unit(xxxx.service)

I find this message misleading. My expecation is that the unit file has been updated with the new content, however that is not the case. Running fleetctl cat xxxx.service shows the old content.

A clearer message would be:

ERROR: Job(xxxx.service) in Registry differs from local Unit(xxxx.service). No change made.

Alternatively, a 'force' flag could be added for those occasions when you really do want to overwrite the unit file. In that case the WARNING message would be appropriate.