Mozilla today released Firefox 55 for Windows, macOS and Linux, debuting options to tweak the browser's performance settings, adding support for the WebVR virtual reality standard and taking a major first step toward dispatching Flash to the Great Software Beyond.
Firefox, which can be downloaded here, updates in the background, so most users need only relaunch the browser to get the latest version. To manually update, click the help icon -- the question mark within a circle -- after pulling up the menu under the three horizontal bars at the upper right. Choose "About Firefox." The ensuing page shows that the browser is either up to date or displays the updating process.