diff --git a/docs/NEWS b/docs/NEWS
index daaee4793..463731013 100644
--- a/docs/NEWS
+++ b/docs/NEWS
@@ -20,6 +20,9 @@ Version 2.6-alpha1 ()
 
    * Block access to .inc php files via .htaccess
 
+   * Make serendipity_sendMail() standard compliant by using CRLF
+     instead of LF to separate headers.
+
 Version 2.5.0 (February 13th, 2024)
 ------------------------------------------------------------------------
 
diff --git a/include/functions.inc.php b/include/functions.inc.php
index cc649189e..8798bde9c 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -564,7 +564,7 @@ function serendipity_sendMail($to, $subject, $message, $fromMail, $headers = NUL
     }
 
     if (!isset($maildata['skip_native']) && !empty($maildata['to'])) {
-        return mail($maildata['to'], $maildata['subject'], $maildata['message'], implode("\n", $maildata['headers']));
+        return mail($maildata['to'], $maildata['subject'], $maildata['message'], implode("\r\n", $maildata['headers']));
     }
 }