Microsoft today released a new Windows 10 Mobile build to Insiders. Now, if you are upgrading from Build 10512, then you may receive Build 10514, as well as Build 10536. What’s interesting is that Insiders will get Build 10536.1000 first, and then 10536.1004. Microsoft states:
Insiders updating from Build 10512 will need to update their devices twice. The first update will be Build 10536.1000. After this update is installed, you’ll receive another update which will be Build 10536.1004. This process will take a bit more time than usual but this update has all the important fixes for Build 10536 so you will want to make sure you take BOTH updates. If you don’t have a problem going back to Windows Phone 8.1, you can update directly to this build (10536.1004).
As Microsoft states, you should upgrade to Build 10536.1000 first and then get Build 10536.1004. Microsoft’s Gabriel Aul explained:
@cyberh0me This is a function of how we had to repackage the update to work around the updategen issue. Will update the blog post to explain
— Gabriel Aul (@GabeAul) September 14, 2015
This is indeed a bad experience, and will take a long time to upgrade to Build 10536.1004 for most Insiders. Nonetheless, hopefully, Microsoft will fix this issue for the next Insider preview release to make the upgrade process better.