The biggest new change in the Mozilla Firefox 83 release appears to be a new security feature called HTTPS-Only Mode, which is implemented in Preferences, under the Privacy & Security section. It provides a secure and encrypted connection between your web browser and the websites you visit, even if they don’t use HTTPS. By default it’s disabled, but when enabled, the HTTPS-Only Mode will upgrade all your website connections to use Secure HTTP (HTTPS). The good news is that it can be used in all windows or only on private windows.