Familiarise yourself with these diagnostic commands (exact syntax may vary by version).

# Show current licence status
ipartition licstat -a
Cause: Many iPartition licence files include both a ValidFrom and ValidUntil field. Some resellers mistakenly sent time-limited evaluation licence files instead of perpetual ones.
Fix: Contact the point of sale. Coriolis Systems is no longer actively supporting iPartition, but some legacy licence generators can produce new perpetual files for verified owners.
If both old and new Macs run High Sierra or older: