The names of several schema field groups have changed. See the document on field group name updates for more information.
IdentityMap is a standard schema field group for the XDM Individual Profile class. The field group provides a single map field, which contains a set of user identities keyed by namespace.
IdentityMap field is automatically updated by the system as identity data is ingested. In order to properly utilize this field for Real-time Customer Profile, do not attempt to manually update the field’s contents in your data operations.
See the section on identity maps in the basics of schema composition for more information on their use case.