Using Managed Apple ID with your own domain has been possible with Microsoft Azure AD and Google Workspace. Later this year, it will become possible to use any domain as long as you support
- OpenID Connect for federated login
- SCIM for Directory Sync
- OpenID Shared Signal Framework (SSF) for account security events like password changes.
(Source) https://developer.apple.com/videos/play/wwdc2023/10254/
I am really happy that SSF was adopted. Congratulations to all the Shared Signals WG members?
Okta will support this option, so any Okta users will be able to utilise this option once available. Even if you are not using Okta, if you support the above three standards, you should also be able to use it.
For details, you can view the video at https://developer.apple.com/videos/play/wwdc2023/10254/ starting from 16:15.