By default, Firefox is set to update automatically but you can always do a manual update. A manual update will still let Firefox download an update but it won't install it until you restart Firefox. Here's how to set it up:

Note: If you use your Linux distribution's packaged version of Firefox, you will need to wait for an updated package to be released to its package repository. This article only applies if you installed Firefox manually (without using your distribution's package manager).

Click the menu button , click Help and select About Firefox.On the menu bar click the Firefox menu and select About Firefox.
The About Mozilla FirefoxAbout Firefox window will open. Firefox will begin checking for updates and downloading them automatically.
When the download is complete, click Restart to update Firefox.

Important: If the update didn't start, didn't complete or there was some other problem, you can go to the Systems & Languages page to download and install the latest version of Firefox for your system and language or you can use this download link (see How to download and install Firefox on WindowsInstall Firefox on LinuxHow to download and install Firefox on Mac for more information).

Stay safe: Download only from the official Mozilla links above to avoid malware and other unwanted programs.

Update settings can be changed in Firefox OptionsPreferences . Click the menu button and choose Options.Preferences. In the General panel, scroll down to the Firefox Updates section.

Firefox

Update Firefox to the latest release