Conrad Stoll has an interesting article on developing for the M7 chip in the latest iOS devices and adapting an app to the motion information returned by the API:

I was already well into developing Runtime when the iPhone 5s was announced and we learned about the new M7 “motion co-processor” from Apple. There have already been a few good articles talking about what the M7 does and how we believe it works, but essentially from a developer’s perspective the M7 provides a great way to track a user’s steps and type of activity while they are moving. Instead of writing about what the M7 is or how it works, I wanted to write about what its like to use as a developer.