Django 1.3 RC 1 was released. Final version can be released maybe next week in optimal case.
Satchmo produces several Deprecation Warnings with 1.3. They can be ignored, but better are small modifications of Satchmo and users application.
I think the oldest supported version is Django 1.2.1, since Jun 2010. (Recommended version is at least Django 1.2.3) Also we can continue without breaking anything and support two main Django releases again.