diff --git a/docs/spec/manifest-v2-1.md b/docs/spec/manifest-v2-1.md
index 9cda0547a..259e3cf65 100644
--- a/docs/spec/manifest-v2-1.md
+++ b/docs/spec/manifest-v2-1.md
@@ -1,8 +1,16 @@
 # Image Manifest Version 2, Schema 1 
 
-This document outlines the format of of the V2 image manifest.  Image manifests
-describe the various constituents of a docker image.  Image manifests can be
- serialized to JSON format with the following media types:
+This document outlines the format of of the V2 image manifest. The image
+manifest described herein was introduced in the Docker daemon in the [v1.3.0
+release](https://github.com/docker/docker/commit/9f482a66ab37ec396ac61ed0c00d59122ac07453).
+It is a provisional manifest to provide a compatibility with the [V1 Image
+format](https://github.com/docker/docker/blob/master/image/spec/v1.md), as the
+requirements are defined for the [V2 Schema 2
+image](https://github.com/docker/distribution/pull/62).
+
+
+Image manifests describe the various constituents of a docker image.  Image
+manifests can be serialized to JSON format with the following media types:
 
 Manifest Type  | Media Type
 ------------- | -------------