I'd like to be able to encrypt the app itself & messages in the same way I can on the open-source protonmail client called ElectronMail ( https://github.com/vladimiry/ElectronMail). This allows me to save messages offline and keep them in an encrypted database as well as encrypting local access to the account that I saved login for. Currently the official linux beta app for mail does not allow securing the app itself at all!