The latest version should work, it works fine for me. If you are having issues such as you see Table of Contents box show up (like a small rectangle) on your pages but you see no links are inside, you have to go into the plugin settings and where it says “Font Size” change it from 0 px to 95 %
If the table of contents box does not show up at all, make sure everything is charged marked under “Heading levels” within the settings.
FYI, I am not affiliated with the developer, I just tested a few settings.