Current FF situation, installed FF 56.0.2 ESR for daily use, thus keeping all good addons in use, security updates until 07\2018. Installed it on top of (replaced) normal 56, it kept all settings, bookmarks, passwords etc, no problems.
Also giving Waterfox (portable) a test, works good as well. A few small details made me prefer it over Pale Moon.
And testing FF 58 (portable), works fine and fast here, before committing need to figure out \ wait for some good replacements \ updates for important addons.