So something strange just happened. Microsoft released the Windows 10 Preview for phones, and contrary to previous rumors two of its flagships did not receive the test version in this first phase.

Reports actually claimed that the Lumia 1020 would also be getting it.

But that claim seemed farfetched even then, considering this is an imaging flagship — not actually easy testing and ironing out all issues in the first preview build of an operating system on all devices. Anyway, these early bits are actually only available on six Windows Phone models right now.

This list includes devices like the Lumia 630, 635, 636, 638, 730 and 830.

The Lumia 930 and Lumia 1520 are curiously missing from this list, and it is worth remembering that these are two expensive flagships that have not even received the Lumia Denim update right now.

So if you are an owner of these two devices, you have no other option than to wait.

But what’s the reason, then?

Microsoft have said that they are now working on a feature called partition stitching.

This new option changes the way that Windows Phones get update, and is why these two prominent flagship devices did not get Windows 10 for Phones Preview in this first wave:

“We have a feature that will be coming soon called ‘partition stitching’ which will allow us to adjust the OS partition dynamically to create room for the install process to be able to update the OS in-place. Until this comes in, we needed devices which were configured by mobile operators with sufficiently sized OS partitions to allow the in-place upgrade, and many of the bigger phones have very tight OS partitions.”
Interesting explanation, but probably not enough to calm disappointed users out there.

The company further confirmed that users that are still on the Lumia Cyan update need not worry, as the Denim update will be here soon.

Now, where have we heard this before, I wonder!