The core of Comet is a multi-functional VOEvent broker. It is capable of receiving events either by subscribing to one or more remote brokers or by direct connection from authors, and can then both process those events locally and forward them to its own subscribers.
In addition, Comet provides a tool for publishing VOEvents to a remote broker.
The latest release is Comet 1.1.0, dated 2014-02-26.
Refer to the release history for earlier versions.