[mdek]

If you want to try these performance improvements (servo, e10s) but keep legacy add-on compatibility (at least for now) I suggest installing firefox 56, disabling auto-updates, and making the following changes/additions in about:config

browser.tabs.remote.autostart true browser.tabs.remote.force-enable true layout.css.servo.enabled true

This way I get to keep my Tree Style Tab, Lastpass, and a few other add-ons that haven't yet been ported to WebExtensions.

Convenient FTP link, since it seems right now the automated installers are jumping between versions 55 and 57: https://ftp.mozilla.org/pub/firefox/releases/56.0b12/

[sammoth]

But then you are probably using the WebExtension compatibility shim which severely reduces the performance gains in the newest versions anyway.

[steveklabnik]

Elsewhere in the thread it's stated that Tree Style Tabs has shipped a 57-compatible version, and that LastPass will be ready by the time this all hits stable.

[mdek]

True. I did in fact have to explicitly downgrade TST to the <57-compatible version. The new version apparently doesn't yet support hiding the tab bar across the top of the browser.

[floatboth]

I think the API for hiding the tab bar hasn't landed yet. You can do that with userChrome.css for now.