How to install Firefox 53 Released with Stability Improvements

   Mozilla Firefox web browser has reached the 53 stable release makes Firefox faster and more stable with a separate process for graphics compositing (the Quantum Compositor). Compact themes and tabs save screen real estate, and the redesigned permissions notification improves usability.

Firefox 51 Changelog : 
New

•     Improved graphics stability for Windows users with the addition of compositor process separation (Quantum Compositor)
•     Two new 'compact' themes available in Firefox, dark and light, based on the Firefox Developer Edition theme
•     Lightweight themes are now applied in private browsing windows
•     Reader Mode now displays estimated reading time for the page
•     Windows 7+ users on 64-bit OS can select 32-bit or 64-bit versions in the stub installer

Fixed

•     Various security fixes

Changed

•     Updated the design of site permission requests to make them harder to miss and easier to understand
•     Windows XP and Vista are no longer supported. XP and Vista users running Firefox 52 will continue to receive security updates on Firefox ESR 52.
•     32-bit Mac OS X is no longer supported. 32-bit Mac OS X users can switch to Firefox ESR 52 to continue receiving security updates.
•     Updates for Mac OS X are smaller in size compared to updates for Firefox 52
•     The last few characters of shortened tab titles fade out instead of being replaced by ellipses to keep more of the title visible
•     Ended Firefox Linux support for processors older than Pentium 4 and AMD Opteron
•     New visual design for audio and video controls

Installation instructions:

    Add the PPA to your system, update the local repository index and install the Firefox package:

$ sudo add-apt-repository ppa:ubuntu-mozilla-security/ppa $ sudo apt-get update $ sudo apt-get install firefox

    Optional, to remove Firefox, do:

$ sudo apt-get remove firefox

To check your Firefox version on Ubuntu, go to Help > About Firefox.