The developer's release is very stable. There are no radical engine changes for 3.1, we are only adding optional filters and plugins, none of which is activated unless you configure it to do so. As a result, you don't get to run any new code
The regression happens during restoration. The problem lies with the ABI restoration script which is included in the backup archive, namely the handling of the #__ metaprefix in INSERT commands. This has been fixed in the dev release.
