6.2.6 Software Compatibility (Looking For Upward Compatible version of OS & DB)

Hello,
we are running windchill  6.2.6 on HP Unix 11 & oracle 9 and looking to upgrade the OS and oracle version to the possible upward compatible versions, can anyone suggest what could be the possible latest OS & oracle I can move on to continue running windchill 6.2.6.

I am looing for some reference who already tried and currently running this old server or have suggestions from their experience. Thanks in advance!!!