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:The letter, sent by Spotify general counsel Horacio Gutierrez to Apple general counsel Bruce Sewell on May 26, suggests that Spotify intends to use the standoff as ammunition in its fight over Apple's rules governing subscription services that use its App store. "This latest episode raises serious concerns under both U.S. and EU competition law," Gutierrez wrote. "It continues a troubling pattern of behavior by Apple to exclude and diminish the competitiveness of Spotify on iOS and as a rival to Apple Music, particularly when seen against the backdrop of Apple's previous anticompetitive conduct aimed at Spotify ... we cannot stand by as Apple uses the App Store approval process as a weapon to harm competitors."