Firefox 56.0: find out what is new. Mozilla will release Firefox 56.0 to the Stable channel on September 29th, 2017. The new Firefox version will be made available to all users of the Stable channel. for more info go here https://www.ghacks.net/2017/09/28/firefox-56-0-find-out-what-is-new/
Firefox 56 is the last Stable version of Firefox that supports legacy add-ons. Firefox 57 Stable will support only WebExtensions.
Mozilla wants to take over our internet safety ! 