Windows 10 for PCs launched on July 29, and now Microsoft and its users are getting ready for the debut of the mobile version, which, according to some sources, should happen in October.

Microsoft too hints that the October release is very likely, as the company says on the official Windows Insider program page that preview builds for mobile devices will expire on October 1, so at that time, everyone should be running a newer version of the operating system.

What exactly a newer version of the operating system means is yet to be determined, but Microsoft says the following in a notification posted on its page:

“Insider Preview expires on October 1, 2015. If you’re running Insider Preview, we'll send you notifications beginning on September 15, 2015 to remind you that it’s time to upgrade your phone to a newer version.”

So basically, starting September 15, you will see notifications to upgrade to a newer build, but it's not yet clear whether this could be the final version of Windows 10 Mobile or just another preview build released in advance of RTM.

The Windows Insider program for PCs continues

Windows 10 Mobile will be offered free of charge to all devices running Windows Phone, so Microsoft plans to upgrade all handsets in one way or another. While it's not clear what will happen with devices that do not upgrade before October 1, WMPU speculates that waiting for carrier approval could be the only chance (and the worst, given the fact that it takes months until they actually do that).

On the other hand, Microsoft might continue releasing new builds as part of the Windows Insider program, as this effort continues on PCs and is very likely to do so on mobile devices too.

As you can see, there are a lot of things that need to be clarified here, so expect several busy weeks for both Microsoft and users testing Windows 10 Mobile.