Jtoakland said

Are both 56.0.2 and 58.0.2 needed?

Absolutely not. In case you have both versions installed : it won't hurt to keep the older version, if for some reason you would want to use that version as well - otherwise just uninstall it.

Thanks so much Happy112!

Do you really have both versions installed or is there only an orphaned (leftover) entry in Windows Control Panel and point both entries to the same Firefox program folder?

Both are installed

Jtoakland said

Thanks so much Happy112!

My pleasure - and thank you for answering cor-el's question  !