Entra ID to Disable Service Principal-Less Authentication

Microsoft will disable service principal-less authentication in March 2026. This step closes a hole that doesn’t exist today but might in the future. The strange thing is that many Microsoft 365 applications seem to use service principal-less authentication. Microsoft will take care of first-party apps before March 2026, but there’s work to do for apps from other vendors.

https://office365itpros.com/2025/04/15/service-principal-less-auth/