[ChildOfThe60s]

I stopped it updating at 53.0.3 & have retained all my add ons.

Primarily I wanted to keep FIRE FTP, which is a simple and easy FTP client that is integrated into Firefox.

That & accessing Easynews is all I use Firefox for anymore.

[daniel1212]

53.0.3 is not esr but anything before 57 should work. https://ftp.mozilla.org/pub/firefox/releases/

[ImJustAnotherOkie]

For FTP try UltraEdit.

Pretty much seamless FTP integration with native files.

Their Telnet is very good too and together makes PC->Unix pretty easy.