Yes, instead of upgrading the source server, I simply moved the 15x domains to the newest SM environment and attached them. They then converted to the newest version. Typically, the best thing to do would have been to upgrade the 15x server first, but that was not an option for this particular migration.
Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
Authorized SmarterTools Reseller
Authorized Message Sniffer Reseller