Microsoft's next phone OS, Windows Phone 8.1, is reportedly set to launch on April 23 alongside a handful of new phones.

The news comes from WPCentral which has the inside track with "various sources" who say that this is the case and that the software is already with the phone makers.

Unfortunately these shady tipsters didn't mention exactly which phones we can expect to see announced in April, but it seems likely that at least one will be a Nokia - the Lumia 630 seems a safe bet.

Building up to it

We're hoping that Microsoft will at least give us a Windows Phone 8.1 rundown at this week's Build conference. Since the company is keen on aligning its mobile and desktop software, this doesn't seem outside the realms of possibility.

And since Nokia was all "hashtag more Lumia" in its Build 2014 teaser, we'd say it seems pretty likely that Windows Phone 8.1 has something to do with it.

We got a nice glimpse at the Windows Phone 8.1 software supposedly running on the Lumia 630 just last week in a video that showed off the updated interface, new Action Centre notifications and new camera software.