Mozilla’s Firefox 51 browser will display a gray lock icon with a red strikethrough in the address bar. A dialog box will pop up with text indicating the connection is not secure. The move follows similar efforts by Google with its Chrome browser. On Tuesday, Mozilla also patched several critical security vulnerabilities in the Firefox ESR version of the browser. The browser also became the first of the major browsers to display a warning to users who run into a site that doesn t support TLS certificates signed by the SHA-2 algorithm.
Source: https://threatpost.com/firefox-51-begins-warning-users-of-insecure-http-connections/123331/