Apple Inc. updated its App Store guidelines Monday with new and clearer language explaining its policy toward cryptocurrency trading and non-fungible tokens, according to Bloomberg. 

Apple has no issue with crypto exchanges or any other apps that allow the trading of digital tokens and currencies as long as those exchanges have the requisite regional licenses to operate where the app is distributed.

Though in order for apps to sell NFTs and related services, they’ll have to go through Apple’s in-app purchase systems and “may not include buttons, external links, or other calls to action that direct customers to purchasing mechanisms other than in-app purchase.”

The fight to funnel payments through Apple’s own payment system, justified by the iPhone maker as the only sure way to secure users and their sensitive information, has spanned legal tussles with Fortnite maker Epic Games Inc. and confrontations with governments like South Korea’s.

Apple specifically guides against any app functionality that lets NFT holders “unlock features or functionality within the app,” which may have served as an oblique workaround to its payments rule. That may affect some NFT projects that use the token like a membership card, providing added perks and access not otherwise accessible. For more, read the full Bloomberg report.