Hi Martin,
Final question:
Would it be better to restore the 7.5 backup into a 7.6 MaxDB and then to upgrade it to 7.8 or to upgrade the empty DB first to 7.8 and then to restore the 7.5 backup into it?
As per SAP note
Note 129352 - Homogeneous system copy with MaxDB (SAP DB)
As of MaxDB Version 7.5, backups can also be imported into target systems in which a higher MaxDB version is running. Example: A backup of Version 7.5.00.50 can be imported into a target system with all of the available MaxDB versions higher than or equal to 7.5.00.50.
Hope this answers your query.
Regards,
Deepak Kori