If you're an avid photographer (and Windows 10 Mobile fan), you'll be happy to learn that Microsoft is requiring that manufacturers include auto-flash on Windows 10 Mobile devices. That might be considered an upgrade of sorts since the most popular Windows Phone handset of all time, the low-end Nokia Lumia 520 (which runs Windows Phone 8.1) didn't even come with a flash.
Some of the other requirements for Windows 10 Mobile that haven't been changed include at least 1GB of RAM and 8GB of native storage. And the same modem-integrated chipsets support the platform. These are the Snapdragon 810, Snapdragon 808, Snapdragon 617, Snapdragon 210, Snapdragon 208, Snapdragon 820 and the Snapdragon 625.