如果您使用IAP（在应用程序购买），您可以将用户购买绑定到单个收据，并验证收据对苹果的服务器。

If you use IAP(In App Purchase), you can tie a users purchase to a single receipt, and verify that receipt against Apple's servers.

对于应用商店购买，而不是IAP，苹果允许，并强迫开发商允许他们的App Store应用程序运行相同的设备作为一个客户可以打开他们的iTunes帐户，没有信息可用的应用程序，这是否是客户的第一次安装或他们的第N。如果该商业模式不适合您，请不要将应用程序出售在App Store中。

For App store purchases, as opposed to IAP, Apple allows, and pretty much forces a developer to allow their App store apps to run identically on as many devices as a customer can put their iTunes account on, with no information available to the app about whether this was the customer's first install or their Nth. If that business model doesn't work for you, don't put the app for sale in the App store.