diff --git a/phpmatrix.php b/phpmatrix.php
index fbb0972..78c4c3d 100644
--- a/phpmatrix.php
+++ b/phpmatrix.php
@@ -297,7 +297,9 @@ class MatrixRoom
     {
         $body = [
             "body" => $html,
-            "msgtype" => "m.html"
+            "formatted_body" => $html,
+            "msgtype" => "m.text",
+            "format" => "org.matrix.custom.html",
         ];
         return $this->client->send_room_event($this->room_id, "m.room.message", $body);
     }