ChangeLog:
Improved page render speed for Windows users with Off-Main-Thread Painting
Loading pages faster by changing how Firefox caches and retrieves JavaScript
Budget-based background timeout throttling has been implemented
Improvements to Firefox Screenshots: Copy and paste screenshots directly to your clipboard, Firefox Screenshots now works in Private Browsing mode
Added Nepali (ne-NP) locale
Added support for form autofill for credit card
Downgrading profile to previous versions is not supported. In case of downgrade, it is suggested to use a new profile
https://www.mozilla.org/en-US/firefox/58.0/releasenotes/