Upgrading

I have a RedHat 7.2 system with 7.2.1-2PGDG (as a server) installed on it.

I installed the PGDG rpm mainly because our RH 7.3 and 8.0 systems seemed to
have problems with the version that was current in the RH 7.2 updates.
Everything has worked great.

However, RH has release new clients (7.2.3-5.73 for RH7.2 systems and
7.1.3-4bp.2 on 7.2 systems) so I would like to update my 7.2 server and
clients.  The 7.1.3-4 installed on the RH7.2 clients works fine
communicating with the 7.2.1-2PGDG server, but I am going to push these up
to what ever version is suggested.

So here is the questions:

1. What version of server should I install on the RH 7.2 system?
2. If I go with the latest 7.3.1 (using the RH 7.3 rpms) will 7.2.3-5.73
clients have any problems communicating?
3. Or should I stick with a lower version?