plesk 8 migration in version 3.56

The plesk migration on plesk 8 was working on 3.55 but is broken in 3.56. I get the following message.

.. validation failed : Not a Plesk 8 backup file : Missing filename for section

this is using the same plesk backup files that migrated before to test that it wasn't the backup file.

Is there a way to go back to the previous version?

Status: 
Closed (fixed)