The changes at Canonical have had an effect both on the priorities for the Mir project and on the resources available for future development. We have been meeting to make new plans. In short:
Mir is alive, there are Canonical IoT projects that use it. Work will continue on Mir to support these and on cleaning and upstreaming the distro patches Ubuntu carries to support Mir.
Canonical are no longer working on a desktop environment or phone shell. However we will maintain the existing support Mir has for compositing and window management. (We’re happy to receive PRs in support of similar efforts.)