Merge pull request #13324 from duglin/BadRCOnVersion

Make version check return 400 instead of 404

docs/sources/reference/api/docker_remote_api.md

@@ -46,6 +46,11 @@ You can still call an old version of the API using
 
 ### What's new
 
+**New!**
+When the daemon detects a version mismatch with the client, usually when
+the client is newer than the daemon, an HTTP 400 is now returned instead
+of a 404.
+
 `GET /containers/(id)/stats`
 
 **New!**

docs/sources/reference/api/docker_remote_api_v1.19.md

@@ -13,6 +13,8 @@ page_keywords: API, Docker, rcli, REST, documentation
  - The API tends to be REST, but for some complex commands, like `attach`
    or `pull`, the HTTP connection is hijacked to transport `STDOUT`,
    `STDIN` and `STDERR`.
+ - When the client API version is newer than the daemon's an HTTP
+   `400 Bad Request` error message is returned.
 
 # 2. Endpoints