According to a report on Recode, Apple has rejected an update to Spotify's iOS app, and that this has caused a "grave harm to Spotify and its customers." The Swedish-based music company competes with Apple's Music streaming app and service. In a letter to Apple's top lawyer, Spotify says that Apple turned down a version of the app citing "business model rules" and demanded that Spotify uses Apple's billing system if it wants to acquire new customers and sell subscriptions. From the report: