Soldato
Well it worked for me. Firefox got me off the old version i was running.....and onto Waterfox which works like a charm (thanks for the heads up Orcvader).
I fired my my Firefox (v56) again the other day and its still rooted... i even left it overnight to see if it just needed time. Firefox lost me as a user over this and im sure im not the only one.
They've rolled out a new fix for 47 to 56 with the blog link I just posted above yours, direct link to the fix for 56 here: https://addons.mozilla.org/en-US/firefox/addon/disabled-add-on-fix-52-56/
On the other hand, WF 68 alpha was released based on Quantum and still has legacy add-ons support, although some will need to be tweaked for compatibility: https://www.ghacks.net/2019/05/09/waterfox-68-alpha-is-out/
Seems to be based on what the Thunderbird team had to do due to also needing to support legacy add-ons. WF is probably the best option for those who don't want to use FF but still want to avoid the Blink/Webkit dominance.