Microsoft Graph Applications API
A Microsoft API that enables you to manage these resources and actions related to applications in Azure Active Directory.
499 questions
As far as I know, this option is not given for the mail resource type. The $deltatoken=latest pattern is only supported for directory resources (users, groups, service principal, applications...) as stated in the documentation. It is supported for drive items with token=latest.
I've also noticed that some members have asked similar questions, so I recommend that you submit user voice to Microsoft to implement the feature for mail resources as soon as possible, and I'll upvote for you.
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