I think it will not a problem if the DC run with an older version if it is the same major release.
The domain command set will not changed too much and an older DC might not send unknown commands.
it is somewhat possible.
compatibilty layer for mixed-domain versions was introduced with 7.1.2 and from that version forward it is compatibile as long as the DC is the latest(newest) version.
That means that you could have 7.1.3 as DC and 7.1.2/7.1.3 on host controllers.
or in future you could have 7.2.0 DC and 7.1.2/7.1.3/7.2.0 on HC.
but 7.1.1 had too many issues on mgmt layer so we decided to not have it as target version.