Upgrading Endpoint Manager 12.1.1 to 12.1.2

I have read the article here http://www.symantec.com/business/support/index?page=content&id=TECH197426 and just want to confirm that there are no other "gotchas" to upgrading SEPM from 12.1.1 to 12.1.2.  Basically, disable SEPM service on all servers, upgrade and fire back up, correct?

My other question is, are we required to upgrade the Endpoint clients at this time or can we continue to run on 12.1.1 and they will function properly.

Thanks