Rated 4 out of 5 stars

by Firefox user c23238 on Aug. 15, 2017 ·

Only version 4.1 is compatible with FF 54 to 56, click on the "View other versions" text on this page and scroll down to version 4.1.
Before you install version 4.1, dont forget to uninstall the previous plugin even if its in disabled form, and restart firefox.
Install the new one only after you removed the old one and restarted.