Firefox 2.03 will fix a lot of security issues but I am sure you didn't even know about them at the first place. However we advise you should install it as it is available as of yesterday.
This version fixed a FTP PASV port-scanning and that was the
only mayor thing fixed in this release.
No matter how do you feel about this update we recommend you go for it as it will make you safer on the net.
You can read more about the release here.