ports security updates branch

[Antoine Jacoutot]

Hi :)

This might be a dumb question, but I was wondering if a king of "stable 
branch" existed for the ports tree. Under OpenBSD I think you can follow 
the ports tree stable branch so you only get security updates for your 
ports.
This does not seem possible under FreeBSD, if I understood correctly 
only the current branch (tag=.) is used for ports; at least this is what 
I always used...
Now, here are my questions about that:
- is there a way to only get the security updates for ports ? (are 
security updates for ports included in the FreeBSD security advisories)
- when upgrading to a new release, can I use the release branch for ports ?

The reason I'm asking this is that I don't want to update my ports 
everytime a new version comes out... except if it has a security issue.

Thanks for reading me.

Antoine