Windows Insider Program Eligibility Shrinks After Windows 10 Mobile CB Release

The gate into the Windows Insider program closed a little tighter today.

Earlier Microsoft started the much anticipated roll out of Windows 10 Mobile (Build 10586.164) upgrade to owners of just 18 Windows Phone 8.1 handsets.

Those handsets, along with six others that were already available in retail channels with Windows 10 installed, now make up the entire handset distribution for Windows 10 Mobile in the Current Branch - aka CB.

A real quick primer on what CB is. Think of it as what we used to call RTM or Release To Manufacturing. That meant it was a stable build of the operating system that is available for all eligible devices. Over time, under Windows as a Service, it will be updated to provide security, bug and performance fixes during its lifetime.

So today's release of Windows 10 Mobile (Build 10586.164) delivers the mobile branch of Windows, formerly referred to as Threshold 2, to its permanent home in Current Branch.

Those devices will now be the stalwarts for Windows 10 Mobile but what about future testing under the Windows Insider Program?

Track Windows 10 Insider Builds for PC and Mobile Devices

Well along with the release of Windows 10 Mobile (CB), Microsoft also provided an update about the Windows Insider Program moving forward as testing of the Redstone development branch continues.

The biggest change is the list of devices that are going to be eligible to continue participating in the testing of Redstone, expected to be released this summer, will be restricted to the 24 devices that are officially supported under Windows 10 CB. You can read more about the changes here.

The Windows 10 Redstone update is expected to be released this summer and three builds have been released for testing in the last month. That release date will be critical for any Windows Insiders who were already testing Windows 10 Build 10586.164 before it became Current Branch today because Microsoft will stop offering updates to that build under the Windows Insider Program at that time.

So if you were testing Windows 10 Build 10586.164 on your device that is now not eligible for the Windows 10 CB upgrade you can continue to use it however, be very aware of the Redstone release this summer when the updates will stop for your device under that build.

At that time you will have to revert back to Windows Phone 8.1 using the Windows Device Recovery Tool in order to continue receiving updates for your handset.

Microsoft has a Q&A available here to explain all the details.