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.
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)