Troubleshoot Firefox 56.0.2 replacement?

[blueblackwow65]

Hi I am presently using 56.0.2 older version of firefox ,I know it is outdated but I still can use some of my legacy addd-ons.I tried new version of Firefox and really disappointed with no addons working from previous version.I am also getting high ram usage (600-1200 megs) from 56 version and high disk usage.
I am now looking for a better browser that can do what firefox is doing with addons now but with much less in ram usage ? Also maybe a portable version.Thks

 

[Prorootect]

may i ask why the 52.5.3 version instead of the 52.6.0. ESR? and also, x32 or x64? thanks

Yes Firefox ESR 52.6.0, 32-bit version, sorry...cause i've copied from my icon on the desktop, which have the ancient nom ...changed now.