You're not using Firefox right now, you're using Chrome 42.
That doesn't necessarily mean you don't also have Firefox installed on your computer, but it does mean that you're not using it right now.
If you want to find out what version of Firefox you have; open and use it to revisit this page - then we'll be able to tell you what version of Firefox you've got.
You need to visit this webpage using Firefox before we can determine if Firefox is up to date on your computer or not.
Firefox will update itself to the latest version each time Mozilla releases a new version. Running the latest version of software helps you to avoid security problems and bugs.
If you need help updating Firefox, you can follow the guide here: How to update Firefox.
If you have any more questions, use the contact form - we'll answer it and include it here too.