As add-ons are programs downloaded from the internet, they are potentially malicious. You should only download add-ons you trust.
This add-on previously supported Anki 2.0. You can download the last version supporting 2.0 here. As Anki 2.0 has been discontinued, no support is available for this version.
All Anki 2.1.x Add-Ons
I use the addon only for Forvo – for Persian and Modern Greek, where your excellent Download Audio is for the moment not yet of any help.
Suggestion: Why not make the Forvo Lookup into a separate addon? I suppose the less technically inclined would be very grateful…