On April 24th, Apple sent an email to participants in the iTunes Affiliate Program that said:
Starting on May 1st 2017, commissions for all app and in-app content will be reduced from 7% to 2.5% globally. All other content types (music, movies, books, and TV) will remain at the current 7% commission rate in all markets. We will also continue to pay affiliate commissions on Apple Music memberships so there are many ways to earn commissions with the program.
The drastic cut in the rate on apps and In-App-Purchases and the short notice took participants in the program by surprise.
The May 1st deadline came and went seemingly without any change to the payout rate on apps. Apple has since posted a clarification to the iTunes Affiliate Resources website that says:
We’d like to clarify some changes being made to the Affiliate Program. Commissions for all iOS in-app purchases will be reduced from 7% to 2.5% globally, and all other content types (including music, movies, books, paid iOS apps and TV) will remain at the current 7%.
Anecdotal evidence since May 1st supports the clarification that the change to affiliate commissions affects In-App Purchases only. Links to apps and other content sold by Apple will continue to earn 7%, which is welcome news for websites and developers who rely on that revenue.