Windows Phone 9
Windows Phone 9 developer preview coming in January next year.msftkitchen

The developer preview version for Microsoft's next major update to its mobile operating system is expected earlier next year, according to a new disclosure.

NokiaPowerUser has received tip from its sources who reveal the Windows Phone 9 will be available for all Windows Phone 8 devices, including Lumia 520, which recently received Lumia Cyan update featuring Windows Phone 8.1.

The sources also mentioned the Windows Phone 9 Preview for Developers will be released sometime in January 2015.

Talking about the new changes, some features might not be available for all devices. Split-screen multitasking, which is already available in Windows 8.1, is expected to be a part of Windows Phone 9. And this would not be surprising considering the Windows for desktop version and Windows Phone getting unified in Windows Threshold.

However, the split-screen multitasking will be reportedly available for smartphones having slightly bigger screen, which will enable users to run apps side by side on the screen. To have this feature, the minimum screen size of the smartphone might be 4.9in or higher.

Another feature that has been rumoured to be coming in future Windows Phone build is Actionable notification. This will enable users to do more with the notifications in Action center and might include responding to messages, apps notifications and reminders from the action center.