Hi,

Thank you for the opportunity to provide a Yang Doctors Early Review for this document.

I have a few general nits about the document (which I might as well raise here), and a few nits with the Yang.  These are all below.  Overall though, the document is in good shape!

Section 1:
  "This documents extends the current" -> "This document extends the current"

Section 2:
  "the verson or the" -> "the version or the"

Section 3:
  "Besides the Subscription ID and the xpath or sub-tree filter"
  ->
  "Besides the Subscription ID and the xpath or subtree filter"

Section 3:
  "This subscription state change notification message is encoded XML"
  "This subscription state change notification message is encoded in XML"

Section 3, figure 5:
  The JSON is missing a comma here:
    "name": "ietf-interfaces"

Section 4:
  "A client can discover the support of 'ietf-yang-push-revision'model"
  ->
  "A client can discover whether the server supports the 'ietf-yang-push-revision' model"

Section 4:
  "This documents extends the 'ietf-notification-capabilities' model with"
  ->
  "This document extends the 'ietf-notification-capabilities' model with"

On feature yang-push-revision-supported:
       description
         "This feature indicates the YANG Subscription Notifications
         supports specifying the list of modules, revisions and
         version in the YANG subscription.";
  ->
       description
         "This feature indicates that YANG Subscription Notifications
         support specifying the list of modules, revisions and
         versions in the YANG subscription.";


On identity incompatible-revision-and-version:
       description
         "The combination of revision and the version are
         incompatible. This failure happens when the revision and the
         version are both specified in the RPC and the YANG
         module supported by the publisher does not support one of the
         revision or the version.";

  ->

       description
         "The combination of revision and version are
         incompatible. This failure happens when the revision and the
         version are both specified in the RPC and the YANG
         module supported by the publisher does not support one of
         them.";

Missing normative references:
RFC 6991 (ietf-yang-types)