BlackBerry has released its BlackBerry 10.3 Software Developing Kit (SDK) beta, and it hints at a new QWERTY keyboard handset.

The handset will have a square screen with a 1440 x 1440 resolution, and a pixel density of 453 DPI.

The resolution matches that of the recently-rumoured Windermere device, and it will be the second QWERTY BlackBerry device this year after the Q20, which is set for a November release.

CEO John Chen has said that BlackBerry will focus on QWERTY phones, as the physical keyboard was always one of BlackBerry’s strong points.

Chen told Reuters in March that "the focus is going to be very keyboard-centric."

On its developer blog announcing the SDK beta, BlackBerry said: "Another important note for developers is that BlackBerry 10.3 is targeted only for new device hardware being introduced later this year. This new hardware will follow our promise of keeping the square screen (1:1 aspect ratio) and 16:9 aspect ratio, including our common 720×720 and 1280×720 resolutions.

"Also, when you fire up the 10.3 beta simulator, you’ll notice another square screen. This is for a new device with a 1440×1440 resolution and pixel density of 453 DPI."

On Tuesday, BlackBerry announced the Z3 Jakarta, and Indonesian-exclusive QWERTY BlackBerry device aimed at the budget smartphone market.