REST API response headers must use the Content-Type application/json value (#489).

CHANGELOG.md

@@ -11,7 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## Fixed
 
 - #480: Make the app GDPR - new EU privacy regulations compliant.
-
+- #489: REST API response headers must use the Content-Type application/json value.
 
 ## [1.3.1]
 

src/engine/Api/V1/Response.php

@@ -143,6 +143,7 @@ class Response {
         $header = $status ? $status->get() : '200 OK';
 
         header('HTTP/1.0 ' . $header);
+        header('Content-Type: application/json');
 
         echo json_encode($this->response, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT);