Apple has begun sending out emails to developers urging them to submit their iOS 7-compatible apps today in order to get them approved before iOS 7 launches to the public on September 18. iOS 7 will feature the biggest changes to the iPhone’s operating system since it launched more than six years ago. Besides the completely revamped UI, there are over 1,500 new APIs and features for developers to take advantage of.

The company has also published a guide for developers who wish to take advantage of the new features the iPhone 5s will offer, including programming for the 64-bit A7 chip, optimizing graphics for OpenGL ES 3.0, and taking advantage of the M7 motion coprocessor and new CoreMotion APIs.

You can follow on Twitter or join our Facebook page to keep yourself updated on all the latest from Apple and the Web.