Update: The full timeline for retirement of Basic Authentication in Exchange Online is now published in Basic Authentication Deprecation in Exchange Online – September 2022 Update.
In February 2021...
Updated Sep 01, 2022
Version 19.0
Blog Post
I just want to make sure I'm understanding where I'm at in all this correctly.
We use a relay server to send mail from our copiers, services, etc., to our Exchange Online / Office 365 tenant. Mail comes in to the local SMTP server (using the server provided as part of IIS), then it connects and sends mail as a specific relay user set up as mailrelay@ our domain. It's using basic authentication, TLS encryption, and TCP/587.
This should still work come October, correct? Because it's authenticating and using SMTP, and SMTP Auth will still be supported.
Where I get confused is that it still shows up when I search the logins for legacy client apps as SMTP. However, it says "Authenticated SMTP" in the details of the log file. I assume that is because it is still basic auth, but of the variety that will still be supported.
So I think I'm good to go for now?