The link which you’re following is outdated and will give you older version of Firefox, I suggest you to follow below link that will give you the latest version of Firefox 41…
How do you update Firefox in CentOS? To be more precise, CentOS 7? I have tried from epel, and they only give me Firefox 38. It doesn’t have Pocket which I need. I did install Firtefox 41 from their website, but it wasn’t an update; it was a fresh install.
As I already mentioned, I did that just the way explained above - but I meant update without me manually removing old and installing a new version of Firefox. Then I remembered that one cannot update CentOS like that, I just type # pacman -Syu in Arch Linux to get latest updates. However, I forgot that CentOS doesn’t work that way, and I had to do it just like you described.
One more question, how do I make it show in applications so that I don’t have to type firefox & every time I want to start it. I use KDE 4.