Recently Mozilla released Firefox 3.6.14 and you’ll be surprised to know Firefox 3.6.15 release. Firefox 3.6.15 release fixes an  issue where some Java applets would fail to load in Firefox 3.6.14.  It is recommended all users to upgrade to the latest version.

Firefox 3.6.15 update

Open Firefox, from Help menu click “Check for Updates” and click Update button if Firefox shows software update.

Read Firefox 3.6.15 release notes.