diff --git a/backend/proxy/README.md b/backend/proxy/README.md
index f3ec7fba..eb1d3ffc 100644
--- a/backend/proxy/README.md
+++ b/backend/proxy/README.md
@@ -31,10 +31,11 @@ To Provide your own configuration file you can create a `default.json` file in t
 
 ## Status Codes
 
-- OutdatedVersions return a `HTTP 404`
-- ActiveVersions return a `HTTP 503` if currently unavailable or the given code by running backend-node
-- Unsupported versions (not configured as outdated or active) return a `HTTP 404`
+- Successfull reponses come with a `HTTP 200`
 - No version header given returns a `HTTP 300`
+- ActiveVersions return a `HTTP 503` if currently unavailable or the given code by running backend-node
+- OutdatedVersions return a `HTTP 426`
+- Unsupported versions (not configured as outdated or active) return a `HTTP 426`
 
 **NOTE:** The default configuration expects the client to set a version header: `X-StApps-Version=<version of app>`
 
diff --git a/backend/proxy/fixtures/visibleRoute.template b/backend/proxy/fixtures/visibleRoute.template
index 678eca88..48eaea9d 100644
--- a/backend/proxy/fixtures/visibleRoute.template
+++ b/backend/proxy/fixtures/visibleRoute.template
@@ -19,14 +19,15 @@ location  {{{ route }}} {
         return 300 'You have to supply a client/app version via the X-StApps-Version header!';
     }
 
-    # Version is unsupported or never existed
+    # Version is unsupported by now or never existed (App/Client has to update)
     if ($proxyurl = unsupported) {
         {{{ cors }}}
-        return 404;
+        return 426;
     }
-    # The version existed, but is outdated now (App should update)
+    # The version existed, but is outdated now (App/Client should update)
     if ($proxyurl = outdated) {
-        return 404;
+        {{{ cors }}}
+        return 426;
     }
     # The version is correct, but backend is not responding
     if ($proxyurl = unavailable) {