Answer:
The updates of the network licenses are linked to internal consecutive numbering.
If the correct sequence is not applied exactly, one of these messages appears.
For Error Code 55, it was probably forgotten to import an older update file.
If you implement the older update first, the new file should subsequently be accepted, too.
For Error Code 54, an outdated C2V file was probably used instead of the up-to-date C2V file. The message appears even if you try to apply the latest update for a second time. In this case, we recommend checking in the ACC (Sentinel Admin Control Center) whether the new programs and/or add-on modules and/or number of licenses are up to date.
http://localhost:1947/_int_/features.html