Whatever you do, don't try to limit your app just if it's running on a jailbroken device. There are many legitimate reasons for Jailbreaking an iOS device. I've

Whatever you do, don't try to limit your app just if it's running on a jailbroken device. There are many legitimate reasons for Jailbreaking an iOS device. I've done it countless times to my devices (fellow iOS developer here), and I've never done so to pirate apps. In order to pirate apps, you must jailbreak. But in order to jailbreak, you needn't necessarily pirate apps.