DeltaChat - an e-mail based OSS messenger
       I know you know WhatsApp, Facebook, Telegram, Threema and Signal. But do you
       know there is one messenger you likely don't know about but have an account
       already? It works fully distributed, supports E2E encryption, allows group
       chats, attachments, offline messages, does not track you, runs on all your
       devices and has multi-client support? 
       Sounds too good to be true? Meet DeltaChat.
       DeltaChat is a messenger application which uses e-mail as backend. It connects
       to your email account and creates a DeltaChat folder. All your chat meessages
       go there. If you export your encryption key from the delta chat app, you can
       also read those messages via email (it uses gpg autocrypt).
       Also, if you write someone from within the DeltaChat app and this person does
       not have DeltaChat installed, this is perfectly fine. He can respond via E-Mail
       and it will work just as well.
       Okay, there are no stickers (yet) and obviouly no phone and video call
       functionality. But other than that, it pretty much ticks all the boxes a
       convenient and secure and free and distributed OpenSource messenger should.
       The setup is as easy as entering your email credentials and everyhing else
       is taken care of.
   URI  * DeltaChat Homepage
   URI  * DeltaChat Clients for Windows, Android, iOS, macOS, Linux and Source Code
       # Changelog:
       # * 2021-01-12: Created