https://www.theverge.com/2018/6/11/17449178/apple-app-store-cryptocurrency-mining-ban-ios-macos

Apple has explicitly banned apps that mine cryptocurrency on its devices, according to newly updated Review Guidelines for the App Store. The new ban extends to all Apple platforms.

In March, Apple removed Calendar 2 from the Mac App Store after the app began mining cryptocurrency on people’s devices in exchange for premium features. It was Apple’s first move against cryptocurrency mining apps. Previously, the company had never done anything about them. At the time, Calendar 2’s developer said Apple removed the app because it violated an App Store guideline: “Apps should not rapidly drain battery, generate excessive heat, or put unnecessary strain on device resources.”