[Samba] general question: mixed releases

[Stefan G. Weichinger]

I am currently upgrading several Debian servers from stretch (9.x) to
buster (10.x).

At that site we run 2 DCs (so far samba-4.10.x) and 2 DMs (one 4.10.x,
one 4.11.x since yesterday)

I assume it's not wrong or problematic to mix releases and have DMs on
4.11 and DCs on 4.10 ?

Anything to consider here?

Is it preferrable to upgrade the DCs first (4.10 -> 4.11) or do the DMs
first (as I started)?

As always we need stability *and* want to use modern software ;-)

Touching the DCs seems more critical to me: more complex, more stuff to
break ...