[Samba] No good way to migrate 4.1 on Server A to 4.7.6 on New Server B

[Mark Amundsen]

> Do you sync idmap.ldb as well ?

> I probably did afterwards without implicitly looking for that file, by re-synching what's under /var/lib/samba.
> After all, things are suddenly working now - after I did those last steps of changing the DNS on the workstations
> to use the new server as its Primary, and changing the roaming profile paths to reflect "isofs2".

I used tdbbackup to synk idmap.ldb, look here:
https://wiki.samba.org/index.php/Joining_a_Samba_DC_to_an_Existing_Active_Directory#Built-in_User_.26_Group_ID_Mappings

-Mark-