XMir not to be enabled in Ubuntu 13.10

Canonical employee Oliver Ries announces "while we are on track to successfully deliver Mir for Ubuntu on smartphones, we are unfortunately not going to be able to deliver Mir +XMir + Unity 7 as the default experience on the desktop.

See here:

I thought this was annouced ages ago? That Mir as default was postponed until the LTS?
I think it’s still available though (not sure if it’s usable, as I’m not sure about the video drivers)