From what I read they weren't setup to host multiple apps and needed a somewhat large refactor to do that. The calendar on beta.protonmail.com is probably what

From what I read they weren't setup to host multiple apps and needed a somewhat large refactor to do that. The calendar on beta.protonmail.com is probably what will be released to production. The only thing to smooth over, from my understanding, is the fact that they did a lot of refactoring to become multi-app. Disclaimer: My understanding could be wrong.