Thank you for your post!
When it comes to the email that you received, I found some similar internal issues and have reached out to the MFA Product Team to confirm if this is a forced feature or if this can be disabled.
In the meantime, on May 8th, if your tenant isn't leveraging Security Defaults, Conditional Access Policies, etc..., the Security Defaults feature will be enabled automatically. However, from my understanding after this is enabled, you should still be able to disable Security Defaults, so that your users who can't use MFA can still get access to your Azure AD tenant.
I hope this helps!
If you have any other questions, please let me know. Thank you for your time and patience throughout this issue.
Additional Links:
- Emergency access accounts - In addition to the recommended action(s), I'd also make sure you have emergency accounts to prevent being locked out of your Azure tenant.
- Raising the Baseline Security for all Organizations in the World
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