This release is compatible with Zotero 8 and Zotero 9 beta. Per BBT 8.0.26, Zotero 7 is no longer supported.
If you use Firefox, make sure to right-click and save the XPI file, not just clicking it.
You can verify you are on the latest version by going into 'Tools' -> 'Addons' in Zotero/Juris-M, clicking the gear icon, and selecting 'Check for updates'