BW 3.5 and Oracle 11G upgrade

Hi

We're running two SAP BW 3.5 systems on Oracle 9.2 and would like to upgrade them to Oracle to 10g or even better 11g.

SP Levels are quite low (respectively SP11 and SP16) and SP upgrades would imply expensive regression tests.

Is there a minimum SP Level required for Oracle 11g ? The 10g upgrade guide mentions a SP9 minimum level for SAP BASIS but nothing is said in the 11g upgrade guide.

Are there some known limitations ?

Thank you