Rated 4 out of 5 stars

FF 50.1 extension disable because it is not signed. Forcing the signature verification to "false" in about:config allow to install, but you cannot drag and drop files anymore, I get an error:

Error message= TypeError: event.dataTransfer.types.includes is not a function
URL= chrome://fireftp/content/js/etc/dragDrop.js
Line Number= 29

This review is for a previous version of the add-on (2.0.29). 

This will be fixed in version 2.0.30 - sorry for the inconvenience. You can downgrade to the previous version in the meantime.