"Apple holds app providers ransom like the Mafia," claims Matthias Pfau, CEO and cofounder of Tuta, an encrypted email provider. The tech giant treats iPhones as its territory, Pfau complains, tightly controlling developers’ access before taking a chunk of their profits. "Anyone wanting to provide an iOS app must pay a ransom to Apple; there’s no way around it."

What can developers do other than agree to Apple's demands if they want to publish iOS apps?