BlackBerry has declared open season for developers on the upcoming OS 10.3 release later this year. They have officially released the SDK OS along with updated roadmaps for the Native, WebWorks, and Android development tools. On top of that they have updated their UI guidelines for the new UI changes. On top of that they have also added a new square screen in the simulator for the BlackBerry Windermere with its 1440×1440 resolution screen and 453 DPI.
Here are the SDK Roadmaps:
BlackBerry is planning some new devices to launch with OS 10.3 this year but they will not be updating current devices until they release OS 10.3.1 later this year with the BlackBerry Classic in November. This is probably because of new features needed to make the upcoming devices features work and avoiding having to go through the hassle they did with OS 10.2 and 10.2.1 through carriers. BlackBerry confirmed that there will be another 10.3.1 SDK released before the Classic comes out to add functionality for the physical buttons on the device.
Check out the full details here