Here’s some bad news for iOS apps using Dropbox’s SDK to tap into cloud storage – which a number of music player apps are doing. Apple has started rejecting these apps, due to the fact that Dropbox’s SDK includes a facility for people to tap through to its website and buy extra storage. This, it seems, flouts Apple’s rules on iOS apps not being able to sell content and services without going through its own in-app purchases system. The company appears to have only just realised that the Dropbox SDK gets around this – hence the rejections. Dropbox says it’s on the case. “Apple is rejecting apps that use the Dropbox SDK because we allow users to create accounts. We’re working with Apple to come up with a solution that still provides an elegant user experience,” says the company’s statement.