[Samba] In-place upgrade from 4.6.12 to 4.7.5 - is it safe?

[Miguel Medalha]

> Yes, that should be safe, as always take backups as every domain is
> unqiue but we have tests for the dbcheck bit and 4.7.5 fixes the
> tombstone bug.

I just upgraded two AD DCs and all looks well. Two previously 
uncorrectable stale DN links that were hanging here for a long time were 
successfully removed by "dbcheck --cross-ncs --fix".

Thank you!