As you may have noticed, Nokia moved on to Fremantle, and there will likely be no more support for the current tablets from Nokia.

You can see Mer as a backport of Fremantle technology to 770, N800, and N810. Nokia is helping the Mer team on hardware and driver issues.

Mer is still in an early stage, so don't expect to use it as your main OS yet. But eventually, it will be able to replace Diablo.