Social Fixer is another browser extension from the same person that brought you Old Layout. It improves your Facebook experience.
Q: Will this still work after everyone is forced into the new layout?
A: I don't know. I think so. I hope so.
Q: Will this work with Social Fixer?
A: Yes! All the features of Social Fixer should work with the Old Layout
Q: How does it work?
A: It tricks Facebook into delivering you the old layout by making your browser pretend to be an older version that their new layout doesn't support
Q: Why do I get a message at the top of Facebook telling me to upgrade my browser?
A: Because Facebook thinks you are using an old browser, it prompts you to update. It doesn't know you are using an updated browser.