NEW Firefox 59.0.2 has been released by Mozilla. the Firefox builtin updater has been UPDATED at this time Staged roll out?, Firefox 59.0.2 breaks compatibility with older versions of the browser and Firefox ESR. Users who want to downgrade are advised to back up their profiles prior to installing the update. Release notes UPDATED https://www.mozilla.org/en-US/firefox/59.0.2/releasenotes/
If you're concerned about privacy in Firefox/Facebook, this extension might be worth looking at for those who haven't already.
https://blog.mozilla.org/firefox/facebook-container-extension/