diff --git a/api-guide/source/extensions.rst b/api-guide/source/extensions.rst
index c9615f0dc8a4..90b6f41e352c 100644
--- a/api-guide/source/extensions.rst
+++ b/api-guide/source/extensions.rst
@@ -2,146 +2,10 @@
 Extensions
 ==========
 
-The OpenStack Compute API v2.0 is extensible. Extensions serve two purposes:
-They allow the introduction of new features in the API without requiring
-a version change and they allow the introduction of vendor specific
-niche functionality. Applications can programmatically list available
-extensions by performing a **GET** on the ``/extensions`` URI. Note that
-this is a versioned request; that is, an extension available in one API
-version might not be available in another.
-
-Extensions may also be queried individually by their unique alias. This
-provides the simplest method of checking if an extension is available
-because an unavailable extension issues an itemNotFound (404)
-response.
-
-Extensions may define new data types, parameters, actions, headers,
-states, and resources.
-
-NOTE: Extensions is a deprecated concept in Nova and their support
-will be removed in a future version. If your product or cloud relies
-on extensions you should work on getting those features into the main
-upstream project.
-
-Important
-~~~~~~~~~
-
-Applications should ignore response data that contains extension
-elements. An extended state should always be treated as an ``UNKNOWN``
-state if the application does not support the extension. Applications
-should also verify that an extension is available before submitting an
-extended request.
-
-
-**Example: Extended server: JSON response**
-
-.. code::
-
-    {
-        "servers": [
-            {
-                "id": "52415800-8b69-11e0-9b19-734f6af67565",
-                "tenant_id": "1234",
-                "user_id": "5678",
-                "name": "sample-server",
-                "updated": "2010-10-10T12:00:00Z",
-                "created": "2010-08-10T12:00:00Z",
-                "hostId": "e4d909c290d0fb1ca068ffaddf22cbd0",
-                "status": "BUILD",
-                "progress": 60,
-                "accessIPv4" : "67.23.10.132",
-                "accessIPv6" : "::babe:67.23.10.132",
-                "image" : {
-                    "id": "52415800-8b69-11e0-9b19-734f6f006e54",
-                    "links": [
-                        {
-                            "rel": "self",
-                            "href": "http://servers.api.openstack.org/v2/1234/images/52415800-8b69-11e0-9b19-734f6f006e54"
-                        },
-                        {
-                            "rel": "bookmark",
-                            "href": "http://servers.api.openstack.org/1234/images/52415800-8b69-11e0-9b19-734f6f006e54"
-                        }
-                    ]
-                },
-                "flavor" : {
-                    "id": "52415800-8b69-11e0-9b19-734f216543fd",
-                    "links": [
-                        {
-                            "rel": "self",
-                            "href": "http://servers.api.openstack.org/v2/1234/flavors/52415800-8b69-11e0-9b19-734f216543fd"
-                        },
-                        {
-                            "rel": "bookmark",
-                            "href": "http://servers.api.openstack.org/1234/flavors/52415800-8b69-11e0-9b19-734f216543fd"
-                        }
-                    ]
-                },
-                "addresses": {
-                    "public" : [
-                        {
-                            "version": 4,
-                            "addr": "67.23.10.132"
-                        },
-                        {
-                            "version": 6,
-                            "addr": "::babe:67.23.10.132"
-                        },
-                        {
-                            "version": 4,
-                            "addr": "67.23.10.131"
-                        },
-                        {
-                            "version": 6,
-                            "addr": "::babe:4317:0A83"
-                        }
-                    ],
-                    "private" : [
-                        {
-                            "version": 4,
-                            "addr": "10.176.42.16"
-                        },
-                        {
-                            "version": 6,
-                            "addr": "::babe:10.176.42.16"
-                        }
-                    ]
-                },
-                "metadata": {
-                    "Server Label": "Web Head 1",
-                    "Image Version": "2.1"
-                },
-                "links": [
-                    {
-                        "rel": "self",
-                        "href": "http://servers.api.openstack.org/v2/1234/servers/52415800-8b69-11e0-9b19-734f6af67565"
-                    },
-                    {
-                        "rel": "bookmark",
-                        "href": "http://servers.api.openstack.org/1234/servers/52415800-8b69-11e0-9b19-734f6af67565"
-                    }
-                ],
-                "RS-CBS:volumes": [
-                    {
-                        "name": "OS",
-                        "href": "https://cbs.api.rackspacecloud.com/12934/volumes/19"
-                    },
-                    {
-                        "name": "Work",
-                        "href": "https://cbs.api.rackspacecloud.com/12934/volumes/23"
-                    }
-                ]
-            }
-        ]
-    }
-
-
-**Example: Extended action: JSON response**
-
-.. code::
-
-    {
-       "RS-CBS:attach-volume":{
-          "href":"https://cbs.api.rackspacecloud.com/12934/volumes/19"
-       }
-    }
+Extensions are a deprecated concept in Nova. Support for extensions will be
+removed in a future release. In order to keep backwards-compatibility with
+legacy V2 API users, the ``extension_info`` API will remain as part of the
+Compute API. However, API extensions will not be supported anymore;
+there is only one standard API now. For the current V2.1 API, ``Microversions``
+are the new mechanism for implementing API features and changes. For more
+detail about microversions, please refer to :doc:`microversions`.