Yesterday Gabe Aul tweeted that Microsoft is working on a new build of Windows 10 Mobile to iron out the bugs in 10586.29.

@aditya_shubhra Yes, we’re working on a new build with fixes for the issues we saw with .29 — Gabriel Aul (@GabeAul) December 16, 2015

Now more detail is available regarding what could be the next build of Windows 10 Mobile released to insiders.

Build 10586.36 has shown up on BuildFeed for internal testing. Unlike the recently released desktop build to insiders this is not a Redstone build, but still TH2, demonstrating that Microsoft is still trying to find that elusive build suitable for pushing out to Windows Phone 8.1 users to upgrade them to Windows 10 Mobile. This was due to start before the end of the year, but recent issues suggest this may be getting somewhat delayed.

We will of course alert our readers as soon as the next build hits the Insider Fast Ring.