Microsoft is working on a new Lumia Smartphone. The unannounced Lumia handset will replace the Lumia 830. Sources say that the Lumia 840 will be launched a few months from now. As such, one would expect it to come with Windows 10 out-of-the-box. But that won't be the case, according to the sources. The Lumia 840 will run Windows Phone 8.1 GDR2. Of course, a Windows 10 upgrade will follow shortly after its launch.

Here's what the Microsoft employee had to say about the Lumia 840:

So, we have some info about one such mid-ranger in works, that may pack Dual-Sim support, 13-14 MP rear camera (PureView), 5 MP FFC, better processor and may sport similar or slightly modified design to Lumia 830. While it is not sure what the name may be, we may call it Lumia 840 for our convenience. This device may have a screen size around 5-inch.

At present, nothing else is known about the Lumia 840. We reckon that the Lumia 830 successor would come with a 5-inch HD display, PureView rear camera, and a mid-range Snapdragon quad-core processor.