How to Retrieve Contacts with List Membership Changes After a Specific Date?

Hi,

I'm working with the Constant Contact V3 API and trying to identify contacts whose list memberships have changed (i.e., added to or removed from a list) after a specific DateTime.

Scenario:

• I added a few contacts to a list and removed a few from the same list via the Constant Contact portal.

• I did not modify any of the contact details themselves.

• When I query the contacts via the API, I notice that the updated_at timestamp on the contact record has not changed, even though their list membership has.

Question:

Is there a way to programmatically retrieve the list of contacts whose list memberships have changed (added/removed) after a given timestamp?

Specifically:

• Is there a different field or endpoint that reflects list membership changes?

• Does Constant Contact track list change history or audit logs that can be accessed via the API?

• Is the updated_at field supposed to reflect list-level changes, or only changes to core contact fields?

Any guidance on how to handle this use case would be greatly appreciated. I want to avoid syncing all contacts unnecessarily and instead fetch only the affected ones based on list changes.

Thanks in advance!