Citation from
http://www.mozilla.com/en-US/firefox/3.6.10/releasenotes/
What’s New in Firefox 3.6.10
Firefox 3.6.10 fixes the following issues found in previous versions of Firefox 3.6:
* Fixed a single stability issue affecting a limited number of users
Similar in the release notes of Seamonkey 2.0.8 .
No security flaws have been fixed.
So if your browser version works correctly, there is
no reason to update.
K-Meleon variations based on Seamonkey 2.0.7,
Firefox 3.5.12 or Firefox 3.6.9 will not have to be
updated for security reasons.
Fred