I am not aware of any difference between standard configuration and MetroCluster. If you use FMC, additional consideration is Brocade switches, but here you follow standard practice of upgrading one fabric at a time and waiting until everything is stabilized before upgrading second one.
Upgrade and Revert Guide is part of standard Data ONTAP documentation pack, available from support (formerly NOW) site. It is also recommended to run Upgrade Advisor which is available on My Autosupport pages.
