Microsoft could add firmware to the Windows Phone Developer Preview13
Of course, that is all well and good unless part of the update is contingent on a firmware update. A couple of examples would be the Bluetooth LE addition that was part of Lumia Cyan, and the improvements to the camera that are a part of Lumia Denim.
But there is some good news. According to Paul Thurrott from the Windows Supersite, Microsoft is considering adding firmware to the software preview that it makes available with the Developer Preview program. This change, if it does take place, probably won't be seen until the Microsoft Build Developer Conference next year, which is scheduled to take place from April 29th through May 1st, 2015. At that point, we could see the firmware included with the Windows 10 Developer preview.