diff --git a/specification/10_client_server_api.rst b/specification/10_client_server_api.rst
index e4e2e58f..8438b40a 100644
--- a/specification/10_client_server_api.rst
+++ b/specification/10_client_server_api.rst
@@ -1092,7 +1092,7 @@ party identifier but the Home Server could not find a matching account in its
 database.
 
 Adding a Third Party Identifier
-===============================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 This section refers to API Version 2. These API calls currently use the prefix
 ``/_matrix/client/v2_alpha``.