Issues migrating to another server

Attempting to migrate (move) a Schooltool instance from an old server to a new server, both running Ubuntu 14.04.

The running version indicates Schooltool 2.8.5 and this is what has been installed on the new server (via APT); however when following the repozo procedure for full backup/restore of the database coupled with cpio backup/restore of the blobs folder there is data missing on the new server, Group membership has disappeared and and the tabs for Grades, Journals - Schooltool otherwise appears to function normally, no errors in logs.

Digging a little further, I found on the running server that the package cache version installed is showing as 2.6.1.2, which is perplexing since the app itself is showing 2.8.5 on the Login page and the Versions section of the Server tab.

So, I tried another migration, this time installing the 2.6.3 release on the new server (which is the only 2.6 release I could find in the archives). Re-did the repozo and blobs transfer. Now schooltool will not start, lots of errors in the logs the most notable an error from ZEO indicating that the internal version of the database is 44 whereas the app is 42.

This seems to indicate that the running version is something > 2.6.3, but less then 2.8.5, despite the information in the package cache or displayed by the app.

Not sure where to go next short of imaging the python distribution and files on the running server and standing them up by hand on the new server.

Any sage advice/guidance/experience on what to look for?

Many thanks