Blog by Tassos Marinos on Tuesday, 27 June 2017
Google Structured Data Markup v2.1.7 is a maintenance release fixing an error occuring on installations working under PHP 5.4 and earlier. It also fixes a warning which was being displayed upon updating the extension via Joomla's Update Manager.
Fixes PHP Fatal error: Can not use method return value. Affecting PHP <= 5.4
Fixes Can't find XML setup file error message during update process