I guess the delay since the last Windows 10 Mobile build (10512) has now gotten long enough and embarrassing enough that Microsoft has felt compelled to comment, I've included some quoted text below. It seems that three major showstopping bugs had been spotted and each had reset the internal approvals process. Ah well, fewer bugs when we next get to see the OS has got to be good, right?

From Gabe Aul's post today:

We’ve received a lot of great feedback on our last Windows 10 Mobile Insider Preview build – Build 10512. In the current build going through our internal rings now most of the known issues introduced with Build 10512 as well as many issues that have been reported have been fixed – mobile hotspot functionality now works, Quiet Hours\Do Not Disturb has been fixed, pinch and zoom in the Maps app now works as expected and the delay in showing the date and time on the Lock screen has been improved. However, as new builds with these fixes passed through our internal rings, we discovered a few issues that we were not comfortable releasing to Windows Insiders until we had fixes for those as well. Each time that happens, we have to do a few things:

1. The team responsible for the area diagnoses the problem and fixes the code.
2. We then verify that the issue is properly fixed, and doesn’t create any side effects.
3. That change then gets integrated into a new build.
4. And we send the build with that fix back through our internal rings.

We have been busy doing this as normal as part of the ring progression process I’ve outlined before – so the train has been moving and overall the builds are getting more robust and reliable. But with each blocking issue, we start back through our internal ring validation with any additional changes that were ready at that time. Unfortunately, we had to reset our ring progression 3 times over the past several weeks because of 3 issues that would have affected Insiders.

It's a nice glimpse into the world of OS development and, given the scope of the changes, I'm not at all surprised. By my reckoning, Microsoft still has about a month and a half to finish the OS before it starts to impact OEMs and its own hardware teams and communities adversely.

Six weeks. Will that be long enough? What do you think?