It's largely overlooked that the success of Slack & MS Teams is partly due to the cybercrime portal that email has become. IOW, you don't get phished in your org's Slack chats. To prevent phishing, any chat service will suffice; an open protocol isn't necessary, as you don't intend to engage with ppl outside your org.
The essential problem IMO is how to replace SMTP. No one has proposed and implemented an alternative, to my knowledge. So I decided to[1]. The current draft omits federation (although I wouldn't rule it out in all cases yet).
The essential problem IMO is how to replace SMTP. No one has proposed and implemented an alternative, to my knowledge. So I decided to[1]. The current draft omits federation (although I wouldn't rule it out in all cases yet).
[1] https://github.com/networkimprov/mnm/blob/master/Protocol.md