And you can't cancel during the trial period either!
To be clear: I'm not passing judgement on the service, it's just weird they don't allow you to stop participating when you want to, and instead you have to wait it out.
Whats bad about this is if you want to test an application on an older version of the software you have to remember to never upgrade the device.
Now that iOS 8 has 80%+ penetration it means that there's still 18% running 7. I'd be very nice to be able to switch back and forth on the same device. because if you're just starting today you can't buy a device with iOS 7 on it new, you have to troll around eBay and Craigslist.