I have a customer with a IPoffice running in basic mode, release 8.1. They wanted to expand. Got them a essential license. Could not load the new format, Had to upgrade to at least release 9. Downloaded release 9.0 of manager, attempted to upgrade, but all it says is "failed to upgrade". I noticed that the main ip 500 v2 module is version 8.1 but some of the other bin files are version 10.1. Is there a work around? should I recreate the sd card? any help??