Comment 4 for bug 1277518

The package is still waiting for build, will be there in an hour or so.

But trunk PPA? It is an untested snapshot of development code, that may break any day without warning. You should reinstall from the dev PPA https://launchpad.net/~schooltool-owners/+archive/dev/ before you enter too much data.

It is not possible to downgrade from 2.7.0dev to 2.6.x, but you can export an XLS file (School export), delete ContactRelationships sheet (incompatible format at the moment), and import into a 2.6 instance.