Encouraging users to downgrade is generally a bad idea, as updates provide critical security updates. Please refrain from doing so unless it's for troubleshooting, when all else fails, '''and''' the user understands that they may be putting themselves at risk using an old version. ''Edit: Please see [https://www.mozilla.org/security/known-vulnerabilities/firefox30.html this], [https://www.mozilla.org/security/known-vulnerabilities/firefox35.html this,] [https://www.mozilla.org/security/known-vulnerabilities/firefox36.html this,] and [https://www.mozilla.org/security/known-vulnerabilities/firefox40.html this] for a list of security issues fixed since 3.0.10.

yea i had 4.0 for two weeks and had more security issues than in 1 year with previous versions, dont use scare tactics to market your opinions.