I know I’m late to the party here, but that’s because I only recently discovered this change after an issue in a live app. Which exemplifies the point I want to make:
@bonjour_17 is absolutely correct. I appreciate that the team had a major abuse issue which led to denial of service for a vast number of users, but that doesn’t justify suddenly and without warning removing a feature that many apps rely on for their operations. Furthermore, doing so with merely a forum post to notify is unacceptable.
The team could have enforced this requirement on new apps while mass-email existing app owners notifying them of the change and giving them a reasonable amount of time to update their systems. Instead, app owners are discovering the change when it is already too late.