In a report to the US Congress a developer working for ProtonMail, makers of an encrypted email app complained that Apple had demanded in-app purchases (IAP), even though Apple had approved its app without them two years earlier -- and that when the dev dared send an email to customers notifying them of the change, Apple threatened to remove the app and blocked all updates.

ProtonMai CEO Andy Yen said that companies were being strong-armed by the most valuable company in the world, ever since Stratechery's Ben Thompson reported that 21 different app developers quietly told him they'd been pushed to retroactively add IAP in the wake of those two controversies. But until now, we hadn't heard of many devs willing to publicly admit it. They were scared.

Yen says developers are still scared, even though Apple changed its rules on 11 September to exempt "free apps acting as a stand-alone companion to a paid web based tool" from the IAP requirement.

Apple explicitly said email apps are exempt but ProtonMail still hasn't removed its own in-app purchases because it fears retaliation from Apple.

Other developers feel the same way, he claims.

"There's a lot of fear in the space right now; people are completely petrified to say anything. For the first two years we were in the App Store, that was fine, no issues there. But a common practice we see ... as you start getting significant uptake in uploads and downloads, they start looking at your situation more carefully, and then as any good Mafia extortion goes, they come to shake you down for some money."