Proton Mail Launches Post Quantum Encryption

Proton relies on the OpenPGP standard, while Tuta just does their own thing. The result being that when using Tuta, only emails between two Tuta users are actually E2EE, and there is no interoperability between other email providers. Both Tuta and Proton do support password protected emails, but those are flawed and, in my opinion, a complete joke compared to proper OpenPGP. So what Proton did is help develop PQE for OpenPGP and then implement it for Proton Mail in a standardized and interoperable way. So I think saying that they "caught up to Tuta” is incorrect.