Fix possible header duplicates when using additional headers (#1489033)

1 files changed, 1 insertions, 2 deletions

diff --git a/program/lib/Roundcube/rcube_imap.php b/program/lib/Roundcube/rcube_imap.php
index 0aa059c26..c67985186 100644
--- a/program/lib/Roundcube/rcube_imap.php
+++ b/program/lib/Roundcube/rcube_imap.php
@@ -3372,7 +3372,6 @@ class rcube_imap extends rcube_storage
     {
         if (!empty($this->options['fetch_headers'])) {
             $headers = explode(' ', $this->options['fetch_headers']);
-            $headers = array_map('strtoupper', $headers);
         }
         else {
             $headers = array();
@@ -3382,7 +3381,7 @@ class rcube_imap extends rcube_storage
             $headers = array_merge($headers, $this->all_headers);
         }
 
-        return implode(' ', array_unique($headers));
+        return $headers;
     }