Currently have one domain and PO in GW 8.0.3 HP1. Server is SLES 10 SP4 and OES 2 SP3.

We want to upgrade to GW 2012 SP1 but are wondering if we should also upgrade to SLES 11 SP2 and OES 11 SP1, and if so, in which order should all this be done? Preferably, we would like to upgrade the current machine, no migration. Any thoughts/advice/experiences and best practices would be greatly appreciated. Thanks in advance.