This question asks how to install FF32 bit while keeping the 64 bit.
I want the much more simple thing: is there a canonical way to install firefox 52 ESR as "default" firefox in my 16.04?
I found this launchpad team ... but there are no packages; probably no wonder given the fact that the linked blog article dates back to 2012.
So, 2017, Ubuntu 16.04; how to install FF 52 ESR (as I simply need the java plugin to work for me).
( my current solution: I downloaded the TAR file from mozilla, extracted that to /opt; and then changed /usr/bin/firefox to be a link to that ESR version of firefox. works, but ugly )