The recommended solution is to Stop all the WAAE Services before taking the backup.
Then take a backup of all the installation files and directories. This steps is Not mandatory.
The R12 will also take a backup of the previous version installation files. However, you can take your own backup.
In case your WAAE Server is on a Virtual Machine, an alternate solution is to take a Snapshot of the Virtual Machine.
When the WAAE databases are “Local” running on the same server as AutoSys, the Snapshot will back up the databases.
Otherwise in case the WAAE databases are on a “Remote” database Server, you will need to make sure to take a backup of the databases with the WAAE Services Stopped at the first step.
The databases backup is Mandatory because the R12 installation procedure will Not take a backup of the databases.
Once the backup of the installation files and directories and databases is completed, you can upload the R12 installation media and perform the in place upgrade.
In case of any problems during the upgrade, you can use the backup of the installation files and directories and databases to restore.
You can consult the following documentation page for more information :