There's a 'Version History - See all versions' link further down the page that points at the previous releases. https://addons.mozilla.org/en-GB/firefox/addon/

There's a 'Version History - See all versions' link further down the page that points at the previous releases. https://addons.mozilla.org/en-GB/firefox/addon/tree-style-tab/versions/ https://addons.mozilla.org/en-GB/firefox/addon/tree-style-ta... and look through teh list til you find something that supports FF52+ I'm a little concerned that any bugs/holes in extensions will be left open though, since it's very unlikely the extension devs are going to be backporting features/fixes.