If you have trouble with the upgrade, use this link; http://www.mozilla.org/en-US/firefox/all/

Open Firefox > from top menu select Firefox and click Preferences > General > Firefox Updates > Check for Updates. It will tell you to restart firefox to complete the update. Done :)

P.S: I'm using FireFox 57.0 (64 Bit)

And yes! It will be better if you allow Firefox to automatically install updates. Likewise you don't have to worry of these issues. Hope it helps :)

naania1432, the OP was using Firefox 52.4.0 ESR which is not on Release channel.

tarunt said

I am using mac os. How can I update my firefox version.? It says up to date(52.4.1) but as i understand there is a newer stable 56 version available

Firefox 52.4.0 is on a ESR channel while the Firefox 56.0 .2 at time was on Release. If you stayed on 52.4.0 ESR then you would have been updated to 52.5.0 ESR a few days ago.