diff --git a/comments.php b/comments.php
index 511e0e2..405920f 100644
--- a/comments.php
+++ b/comments.php
@@ -223,7 +223,7 @@ function commentform() {
 				), $lang ['comments'] ['mail']);
 
 				// for non-ASCII characters in the e-mail header use RFC 1342 — Encodes data with MIME base64 and splits the encrypted subject
-				@utils_mail($from_mail, "=?utf-8?B?" . base64_encode($lang ['comments'] ['newcomment']) . "=?= =?utf-8?B?" . base64_encode($fp_config ['general'] ['title']) . "==?=", $mail);
+				@utils_mail($from_mail, '=?utf-8?B?' . base64_encode($lang ['comments'] ['newcomment']) . '=?= =?utf-8?B?' . base64_encode($fp_config ['general'] ['title']) . '==?=', $mail);
 			}
 
 			// if comment is valid, this redirect will clean the postdata