Let's assume the EU does the following things:
- It develops a messaging standard for texts, speech messages, documents, video calls, end-to-end encryption and more and makes this open source (like the Email-standard for emails). This standard allows communication between apps by different developers. It could be an extension of the matrix communcation standard or Rich Communication Services (RCS) protocol.
- It makes it obligatory by law for every messenger (e.g. WhatsApp, Skype, iMessage ...) to use this standard.
This means that every use can use the messenger client of their choice to communicate with every other user independent from the app/client they are using. For example I could write an iMessage in a group chat with other users using WhatsApp and Skype respectively. Clearly that would be a huge consumer benefit increasing consumer welfare and it would foster competition between app developers.
Would the EU be allowed to do so and make the use of such a standard obligatory instead of voluntary?