It does indeed use version information, not just the browser's but also of every installed plugin including Flash. So a single rev is going to give a new fingerprint. Plus, far fewer people are checking it as when it first launched, making those who do check it from time to time even more unique.
But note that a constantly changing fingerprint doesn't make it useless for tracking - if a site can keep any kind of cookie to persist between browser updates, it could add the updated signature. Then when you purge cookies and persistent storage, a site can re-add the cookie to keep on identifying you if your signature hasn't changed.
You'd have to purge all persistant storage at the same time as an update to avoid this, and even then (or if you never had persistent data to begin with) your IP or even geographical location will likely be enough to identify you again.
But note that a constantly changing fingerprint doesn't make it useless for tracking - if a site can keep any kind of cookie to persist between browser updates, it could add the updated signature. Then when you purge cookies and persistent storage, a site can re-add the cookie to keep on identifying you if your signature hasn't changed.
You'd have to purge all persistant storage at the same time as an update to avoid this, and even then (or if you never had persistent data to begin with) your IP or even geographical location will likely be enough to identify you again.