unless you want to loose the extensive capabilities provided via classic Firefox extensions. If you did not want to loose you extensions with the advent of (the fast but relatively handicapped) Firefox Quantum, do not update to Firefox 60 esr, which will actually be an "update" (downgrade for power users) to Quantum. Which means most of your extensions will not work, including, Tab Mix Plus 0.3.8.6 https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plusReduce tab width; Enable multiple tab rows; Change how active tab looks, etc.Memory Restart https://addons.mozilla.org/en-US/firefox/addon/memory-restart/ Shows how much ram FF is using, and enables easy restart to flush memory.ColorfulTabs https://addons.mozilla.org/en-US/firefox/addon/colorfultabs/?src=search/ Make tabs distinctive. Options...