Your appliance must be upgraded to release 12.1.2.5, and you must ensure that you can upgrade to Oracle Linux 6.
Ensure that you complete these requirements before you start your upgrade to Oracle Database Appliance 12.1.2.6
Upgrade to Oracle Database Appliance 12.1.2.5
Before you upgrade to Oracle Database Appliance release 12.1.2.6, you must have already upgraded successfully to Oracle Database Appliance release 12.1.2.5.
If you need to upgrade to the Oracle Database Appliance 12.1.2.5 patch set, then refer to Oracle Database Appliance Administration and Reference Guide for release 12.1.2.5 and carry out upgrade instructions:
Oracle Database Appliance Administration and Reference Guide, Release 12.1.2.5Verify That You can Upgrade Your Oracle Linux 5 Operating System to Oracle Linux 6
Oracle Database Appliance 12.1.2.6 includes an upgrade of your Oracle Linux operating system from Oracle Linux 5 to Oracle Linux 6. Before unpacking the patch, you can use the pre-check tool provided for Oracle Database Appliance 12.1.2.6 to ensure that you can upgrade your Oracle Linux operating system. To run the pre-check tool, refer to the release notes for Oracle Database Appliance for instructions. After you unpack the 12.1.2.6 patch on Oracle Database Appliance, you can run the command oakcli validate -c ol6upgrade -prechecks to carry out prechecks on the appliance.