Will an on-prem Exchange Server (operating in a Hybrid Setup) continue to support BASIC AUTHENTICATION via IMAP and EWS?
We know that Microsoft is disabling BASIC AUTHENTICATION for Exchange Online. We have an application that still uses BASIC AUTHENTICATION over IMAP/EWS to retrieve emails by connecting to the on-prem Exchange Server (not the Exchange Online endpoints).
We were wondering if it will stop working when Microsoft disables BASIC AUTHENTICATION on the online part of the Hybrid setup.
Note: The plan is to upgrade the software to use MSGraph and Microsoft Modern Authentication.
If you have security defaults enabled, basic auth will be blocked but if you are using conditional access policies you can exempt any/all users from blocking legacy auth. I've seen this used in a lot of cases where legacy on-prem apps still need to connect via EWS/SMTP/IMAP.
When/If Microsoft decides to completely disable basic auth, a LOT of on-prem apps will stop functioning.