The availability of FreeBSD 6.0-BETA1 was just announced. The security team will support the branch for 2 years after the final release. The earliest that RELENG_5 will be de-supported is late 2007. The migration work for users from 5.x to 6.x is very small. It should be quite easy to deploy and maintain. 5.5 release this fall and possibly a 5.6 release a few months after that. If I were planning on installing a new server next month, I’d install.”]
Source: https://taosecurity.blogspot.com/2005/07/freebsd-6.html