The Nokia Lumia 630 leaked in February as the first Windows Phone with buttons on screen. Now it's appeared online again, this time with its camera being tested and the much-anticipated Windows Phone 8.1 on board, ahead of a possible appearance at Microsoft's Build 2014 developers conference.

Sofica, a site for testing cameras, had the model number RM-964 appear in its CamSpeed test. This is the code associated with the Nokia Lumia 630 according to Indian shipment data site Zauba.

The Lumia 630 was clocked with a 5-megapixel camera without a flash. This fits with the @evleaks photo of the device previously shown. According to the Zauba leak the price is 7872 Rupee which is about £78. This affordable tag would be possible with such a low spec camera.

The CamSpeed data also revealed that the Lumia 630 was running Windows Phone 8.1 with version 8.10.12324.0. That would make this one of the cheapest Windows Phone 8.1 Phones on the market. And, well, it's Windows Phone 8.1, which we're still to hear about officially.

We're not yet sure whether the Lumia 630 will be just for India or released globally. That remains to be seen.

Expect Nokia to unveil the Lumia 630 at Build from 2 April.

READ: Nokia Lumia 630 leaks as first Windows Phone with on-screen buttons