I have reviewed this document as part of the Ops area directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written primarily for the benefit of the Ops area directors.
Document editors and WG chairs should treat these comments just like any other last-call comments.

Summary: This draft focuses specifically on synchronizing contacts data using JMAP. 



Section 1.3 says: "In servers with support for JMAP Sharing", data may be shared with other users. 

Question 1: for servers that don't support JMAP, is the data model specified in this document only for "Sharing Contacts" but not other information? 

Question 2: Does this document extend the data model specified in draft-ietf-jmap-sharing-07 for sharing Contacts?

Thanks, Linda Dunbar