This illustration shows the flow of steps when upgrading either a 9.0.4 configuration where all components are at the same Oracle Application Server version.

During the upgrade, you can begin by upgrading the middle tiers, or by upgrading OracleAS Identity Management. By following either path, you encounter transitional upgrades where the middle tiers are running a different version of Oracle Application Server than the OracleAS Metadata Repository. In the end, however, if you follow the documented steps in the process, you can end up with a final configuration where all components are upgraded to 10g Release 2 (10.1.2).