Last January, Microsoft made the bold promise that it would upgrade all Windows Phone 8.1 devices to Windows 10. As many of us remember, the company broke that promise, allowing Insiders to continue receiving updates for a time but giving them absolutely no notice.

Devices that lost support included those with less than 1GB RAM, less than 8GB of storage, or a Snapdragon S4 processor, along with a few miscellaneous third-party devices, such as the HTC One M8. Eventually, any upgrade path was removed for all of these devices, so if you hadn't gotten Windows 10 already, there was no legitimate way to do so.

But that seems to have changed. Today, Microsoft released the Windows 10 Mobile Creators Update to the Release Preview ring of the Insider Program, effectively ending support for another subset of Windows phones. Naturally, the Internet figured out that something unintentional was happening: some of those older devices were coming back to life.

@TheRichWoods seems to be available to the 520 and 635 512MB model — Francie Mc Cool (@mccools2013) April 25, 2017

The anomaly seems to only affect devices with 512MB of RAM, or at least that's what we've found so far. When we tested it out on a Nokia Lumia 1020 and an LG Lancet, there were still no updates; however, the 512MB Lumia 635 and Lumia 520 do seem to work, as you can see from the image above.

The first build that it will install will be one from the Threshold 2 branch, but apparently, Francie has been able to take a Lumia 520 all the way to the Creators Update using this method.

It's not clear why this is happening, but if you had always wished that your old Windows phone got Windows 10, now's the time to get it. You can be sure that Microsoft is going to shut this down as soon as it realizes that something is wrong.

Are you able to upgrade your old Windows phone to Windows 10 Mobile? Let us know what device it is in the comments!