1 files changed, 2 insertions, 1 deletions
diff --git a/lib/Fetcher/Client/FeedIoClient.php b/lib/Fetcher/Client/FeedIoClient.php
index 268828e2b..33a3db2ad 100644
--- a/lib/Fetcher/Client/FeedIoClient.php
+++ b/lib/Fetcher/Client/FeedIoClient.php
@@ -44,10 +44,11 @@ class FeedIoClient implements ClientInterface
      */
     public function getResponse(string $url, \DateTime $modifiedSince) : ResponseInterface
     {
+        $modifiedSince->setTimezone(new \DateTimeZone('GMT'));
         try {
             $options = [
                 'headers' => [
-                    'If-Modified-Since' => $modifiedSince->format(\DateTime::RFC2822)
+                    'If-Modified-Since' => $modifiedSince->format('D, d M Y H:i:s e')
                 ]
             ];