A bit of historical context. Glass unofficially supported Bluetooth keyboards up to version XE11 (that is, November 2013). Version XE12 contained one major bug

A bit of historical context. Glass unofficially supported Bluetooth keyboards up to version XE11 (that is, November 2013). Version XE12 contained one major bug which, while it didn't break keyboards themselves, did break most of the non-Glass Android apps you'd want to use a keyboard to control. Version XE16 was a four-month rewrite, which replaced the Bluetooth stack with one that couldn't handle keyboards (and bricked a lot of devices and broke a lot of other things.) At that point something went very very wrong with Google's internal politics, and despite there being both internal and external demand, work to repair keyboard support was blocked in favor of fixing crash-bugs. Combined with Glass being closed-source, an overly-aggressive auto-updater that made it hard to stay on XE11 or XE12, increased memory usage that exceeded what the existing units had, and poor communications from Google, this caused the Glass community to turn on Google and become hostile. Three years later, version XE23 adds support for Bluetooth keyboards, and makes it more official (so you don't need an awkward procedure involving sideloading parts of cell-phone Android). So I interpret this a sort of three-years-later apology. For which, thank you, it's overdue but is a nice gesture. Source code would also be nice, as would a public post-mortem of what the whole mess looked like from Google's end.