Mozilla released an update to Firefox on January 13, 2015 with Firefox 35. There are several new features and fixes for this release and these can be viewed in the release notes.
Users may be prompted to update to the newest release (35.0) of Firefox or can do so manually within Firefox by going to Help > About Firefox and following the update prompts. Users may also manually download and install the newest Firefox update (34.5 via the getfirefox.com site. The next scheduled update for Firefox is February 24th, 2015 with Firefox 36.