After you have prepared your existing configuration, you
can begin the Application Engine upgrade.
The tasks for upgrading Application Engine differ
depending on whether
you start from version 3.5 or version 4.0.
Upgrading Application Engine from 3.5
An upgrade from version 3.5 resembles a new install. You
can choose to upgrade Application Engine interactively
by using the upgrade wizard, or silently by using a silent input file.
Upgrading Application Engine from 4.0
In an upgrade from version 4.0 or later, the upgrade tool
verifies that the currently installed version of Application Engine can be upgraded. You can
choose to upgrade Application Engine interactively
by using the upgrade wizard, or silently by using a silent input file.