The second page of the wizard displays the schema
versions available for upgrading the database.
The wizard displays only the schema versions that
are newer than the database's current version. If the schema is currently
checked out, this list does not include the version number associated with
the checked out schema.
Note: You cannot revert
a database to an earlier version after you upgrade it. Before upgrading the
database, you can create a backup copy by using your database utilities.