should be no issues at all, read the documentation, which basiclly has you "lock" the translations for upgrade on the active server, then upgrade the standby server (apply the CM 3.1.4 patches and make upgrade permanent), then interchange (this causes the entire system to reset, and makes the server you just upgraded active), now upgrade the old active server (now standby), apply patches, make upgrade permanent, and you are all set.
Mitch
AVAYA Certified Specialist