Try reading docs/install.html in installation package before posting here. Everything is written there in section 'Upgrading from 1.2.*'

2

(13 replies, posted in General discussion)

http://www.frsirt.com/exploits/20050507.firefox0day.php
Bug 293302 - Firefox 1.0.3 Critical Vulnerability
http://it.slashdot.org/article.pl?sid=0 ? p;from=rss

To protect yourself against all of these holes, disable JavaScript. (Some people have suggested only disabling software installation. If you only disable software installation, you will still be vulnerable to the XSS hole used in the exploit. XSS is sufficient for stealing cookies, saved passwords, intranet web pages, etc.)