You must test this without MDL-50784 integrated / in your branch. Open the template library, In another browser tab log out Use the template library without reloading the page - it should still work (because the webservices it uses do not require a session). Edit lib/db/services.php Change 'core_output_load_template' => array( 'classname' => 'core\output\external', 'methodname' => 'load_template', 'description' => 'Load a template for a renderable', 'type' => 'read' ), to: 'core_output_load_template' => array( 'classname' => 'core\output\external', 'methodname' => 'load_template', 'description' => 'Load a template for a renderable', 'type' => 'write' ), Use the template library without reloading the page - it should show exceptions "Web service is not available (it doesn't exist or might be disabled)".