diff --git a/app/classes/Framadate/Services/MailService.php b/app/classes/Framadate/Services/MailService.php
index 8e427d8..b56acce 100644
--- a/app/classes/Framadate/Services/MailService.php
+++ b/app/classes/Framadate/Services/MailService.php
@@ -58,7 +58,7 @@ class MailService {
             $mail->msgHTML($body, ROOT_DIR, true);
 
             // Build headers
-            $mail->CharSet = 'UTF-8';
+            $mail->CharSet = PHPMailer::CHARSET_UTF8;
             $mail->addCustomHeader('Auto-Submitted', 'auto-generated');
             $mail->addCustomHeader('Return-Path', '<>');
             $mail->XMailer = ' ';