Apple has given Damus, a decentralized social media app, a warning that it will be removed from the App Store if it doesn't update to comply with Apple's policies. The warning is due to Damus's "zaps" feature, which allows users to earn bitcoin on posts. Apple requires tips or donations to use in-app purchases if they are connected to or associated with receiving digital content. Damus may have to remove the zaps feature to stay on the App Store, which could hinder bitcoin applications trying to innovate on lightning.