THE MOZILLA ORG said that the latest update to Firefox 1.5 is the last. The version won't receive any more updates.
Instead, the org said, people using Firefox 1.5 will be prompted to download 1.5.0.12 which includes software to allow an upgrade to Firefox 2.0.
The Firefox 2.0 upgrade for users of 1.5 will be released in the next few weeks. Mozilla director Basil Hashem said that the org's highest priority was security. Users of 1.5 might be vulnerable in the future