My Firefox addon Happy Jogustine has reached end of life. I will not continue the development and starting with Firefox Release 57 the addon does not work anymore.
With the upcoming Firefox Release 57, released in november, only addons based on the new API WebExtensions are supported. See Firefox add-on technology is modernizing. Old addons using XUL or the addon-sdk, which is used by the project, are deprecated.
If you are using the Firefox nightly build or just waiting until Firefox 57 is released, you will see the following note in the Add-ons menu:
Since the usage count of this addon has dropped (only a few computers are polling the update manifest) and I'm not using the addon myself anymore, I have decided not to port the addon the new WebExtensions API. Nevertheless it would be a fairly easy task to do it, but I don't have the free time anymore.
I would like to thank all the users of the addon since the first release in 2013 and the developers behind the addon SDK who worked on my first public bug report: add argument to include updateKey in install.rdf. At that time it seemed that I was the only user of the addon SDK who self hosted the XPI and update manifest.