The Coalition for App Fairness (CAF), a newly formed advocacy group pushing for increased regulation over app stores, has more than doubled in size with today’s announcement of 20 new partners — just one month after its launch. The organization, led by top app publishers and critics, including Epic Games, Deezer, Basecamp, Tile, Spotify and others, debuted in late September to fight back against Apple and Google’s control over app stores, and particularly the stores’ rules around in-app purchases and commissions. The coalition claims both Apple and Google engage in anti-competitive behavior, as they require publishers to use the platforms’ own payment mechanisms, and charge 30% commission on these forced in-app purchases.