iOS developers all share the common knowledge that one of the most tedious processes in having a successful iPhone or iPad app is to pass Apple's submission system. In order to have an app submitted to iTunes, the developers must ensure full compliance with all of Apple's guidelines.
The latest illicit feature Apple has discovered in iOS apps is the use of Dropbox's SDK, with Apple's teams currently in the process of removing apps linking to a Dropbox desktop version.
"Reason for rejection is the fact that if the user does not have Dropbox application installed then the linking authorization is done through Safari (as per latest SDK). Once the user is in Safari it is possible for the user to click "Desktop version" and navigate to a place on Dropbox site where it is possible to purchase additional space," details iOS developer Goran Daemon Peuc in his comment relating to this issue.
Apple regards the situation as sending its potential customers to an additional purchase. iOS apps cannot "provides access to external mechanisms for purchases or subscriptions to be used in the app," says Apple in a letter to developers.
Affected iOS developers have asked Dropbox to remove the Desktop version link from the mobile authorisation site, in order to have a chance of submitting their apps.