user.lastChangedDate for efficient retrieval of user updates

[felix-schwarz]

I noticed that, in responses, for user and identity.user objects only the user.identifier is provided, but not the displayName. I understand/guess this is probably for efficiency / performance reasons.

From the client perspective, however, this raises the question on how often to query the /users endpoint to retrieve information on users and keep it up-to-date.

My idea here is that I could probably use OData to query only for users whose records were created or updated since the last time the client checked. I'd need a lastChangedDate property for that, though.

All I could find was lastPasswordChangeDateTime, which tracks only password changes.