@@ -390,8 +390,10 @@ Get stdout and stderr logs from the container ``id``

 **Example response**:

-       HTTP/1.1 200 OK

+       HTTP/1.1 101 UPGRADED

        Content-Type: application/vnd.docker.raw-stream

+       Connection: Upgrade

+       Upgrade: tcp

        {{ STREAM }}

@@ -406,7 +408,8 @@ Query Parameters:

 Status Codes:

--   **200** – no error

+-   **101** – no error, hints proxy about hijacking

+-   **200** – no error, no upgrade header found

 -   **404** – no such container

 -   **500** – server error

@@ -641,8 +644,10 @@ Attach to the container `id`

 **Example response**:

-        HTTP/1.1 200 OK

+        HTTP/1.1 101 UPGRADED

         Content-Type: application/vnd.docker.raw-stream

+        Connection: Upgrade

+        Upgrade: tcp

         {{ STREAM }}

@@ -660,7 +665,8 @@ Query Parameters:

 Status Codes:

--   **200** – no error

+-   **101** – no error, hints proxy about hijacking

+-   **200** – no error, no upgrade header found

 -   **400** – bad parameter

 -   **404** – no such container

 -   **500** – server error

@@ -1739,7 +1745,18 @@ As an example, the `docker run` command line makes the following API calls:

 ## 3.2 Hijacking

 In this version of the API, /attach, uses hijacking to transport stdin,

-stdout and stderr on the same socket. This might change in the future.

+stdout and stderr on the same socket.

+

+To hint potential proxies about connection hijacking, Docker client sends

+connection upgrade headers similarly to websocket.

+

+    Upgrade: tcp

+    Connection: Upgrade

+

+When Docker daemon detects the `Upgrade` header, it will switch its status code

+from **200 OK** to **101 UPGRADED** and resend the same headers.

+

+This might change in the future.

 ## 3.3 CORS Requests