The update is due to the Google platform directives. The Synchronize option no longer exists: if you make a configuration change on the control panel, the APP does not update. To get the synchronization you need to set the changes from the APP and send them via SMS. The same for the modification of the secret code.
From the Elkron website, you can download the previous version https://www.elkron.it/Prodottiesoluzioni/Catalogoonline/tabid/89/idprodotto/79989/language/en-us/Default.aspx