Details emerge on Microsoft's Lumia 550, the Windows 10 Mobile successor to its Lumia 640

Next month, all eyes will be on Microsoft, as the company is expected to unveil its Surface Pro 4 tablet, second-gen Band wearable device, and its long-awaited Windows 10 Mobile flagships, the Lumia 950 and 950 XL. These two high-end handsets have been the talk of the Windows community for months - but what of the rest of Microsoft's new, smaller Lumia range?

Details emerged today on an upcoming low-end device, known by its development codename 'Saimaa'. Expected to launch as the Lumia 550, the Windows 10 Mobile handset was spotted by WinFuture.de on a somewhat barebones listing at one of the company's European distribution partners. However, that listing only a provided a few insights into what the device will offer - but a few more gaps have since been filled in.

The Lumia 550 is expected to replace the Lumia 640 (pictured), which launched in April

Windows Central reports that it has seen the Lumia 550 in the flesh, describing it as looking "exactly like the current Lumia 640" - which is perhaps unsurprising, given that it will eventually replace the 640 in Microsoft's range. According to that site's editor-in-chief, Daniel Rubino, the 640 will be Microsoft's last 600-series Lumia device for the foreseeable future:

simple, this is not a 6xx series phone. There are no more 6xx for now RT @potasiyam @Daniel_Rubino How a Snapdragon 210 replaces 400?
— Daniel Rubino (@Daniel_Rubino) September 15, 2015

The report also lists key specs and features of the device:

1280x720px AMOLED (the Swiss listing stated that the size is 4.7-inches)
Quad-core 1.1GHz Qualcomm Snapdragon 210 processor
8GB onboard storage
microSD card slot
On-screen Back, Start and Search buttons
Glossy white or black options, with 'metal around the display'
4G LTE connectivity

Evidently, there are still some details that haven't yet been clarified, such as how much RAM the handset will have. But the report did reveal that the Lumia 550 will include a front-facing flash for the front-facing camera, aligning with recent rumors that Microsoft was working on a device with this feature.

It's not exactly clear when the Lumia 550 will be officially unveiled, but there are no indications that Microsoft will do so at its event next month. Indeed, it seems likely that it won't arrive until early 2016, Mobile World Congress - where Microsoft announced its Lumia 640 and 640 XL earlier this year - could present the ideal opportunity next February.

Source: WinFuture.de / Windows Central