Rated 5 out of 5 stars

The extension works near flawlessly with Horde Kronolith.

There is one bug with Thunderbird 3+ when there are a lot of events supplied in the freebusy file. When parsing, it generates incomplete lines that result in errors. I fixed it in a home version 2.1.1 and it works great now.

I don't understand why the 2.1 version is part of the older files.