diff --git a/lib/htmloutputter.php b/lib/htmloutputter.php
index 64be745beb..c70f965376 100644
--- a/lib/htmloutputter.php
+++ b/lib/htmloutputter.php
@@ -106,7 +106,7 @@ class HTMLOutputter extends XMLOutputter
             }
         }
 
-        header('Content-Type: '.$type.'; charset=UTF-8');
+        header('Content-Type: '.$type);
 
         $this->extraHeaders();
         if (preg_match("/.*\/.*xml/", $type)) {
diff --git a/lib/util.php b/lib/util.php
index 44a3772200..d249b154fc 100644
--- a/lib/util.php
+++ b/lib/util.php
@@ -1165,7 +1165,7 @@ function common_negotiate_type($cprefs, $sprefs)
     }
 
     if ('text/html' === $besttype) {
-        return "text/html";
+        return "text/html; charset=utf-8";
     }
     return $besttype;
 }