Apple’s new smart battery case recently hit the market with the aim of helping iPhone 6 and 6s users get a little more life from their battery. The release has come as a surprise to even some of the biggest Apple fans, since the product showed up with almost no fanfare.

While more and more iPhone users are installing the new iOS 9, there are still thousands of us holding out on the upgrade as we wait to hear more about it. So if you’re curious to know what kind of new features you’re missing out on, and if there are any downsides to the new OS, you are in luck.