Mir 2.16 contains a rework of its graphics platform APIs, integration so Mir can provide for a "seamless" boot experience, improved support for X11 clients via a number of bug fixes, virtual output display platform support, input-method-v1 Wayland protocol for maliit-keyboard support, and a variety of other feature changes and bug fixes.
Canonical's focus on Mir appears to continue to be driven by commercial needs around Ubuntu Core use-cases for Mir powering various smart devices . Mir has also been making inroads helping to serve as a Wayland compositor for other desktops .
More details on today's Mir 2.16 release via Ubuntu Discourse and the code for those interested can be found on GitHub .