DutchDaemon said:
Ok

I thought there was a way to stay on a specific X.Y-STABLE branch (which I've never done, so I guess I invented my own RELENG scheme!).
7-STABLE and 7.3-STABLE are currently the same thing.
RELENG_7 is the tag to use.
If you upgrade to RELENG_7 after installing 7.0 and before 7.1 is released, uname will show 7.0-STABLE.
If you upgrade to RELENG_7 after installing 7.1 and before 7.2 is released, uname will show 7.1-STABLE.
If you upgrade to RELENG_7 after installing 7.2 and before 7.3 is released, uname will show 7.2-STABLE.
If you upgrade to RELENG_7 after installing 7.3 and before 7.4 is released, uname will show 7.3-STABLE.
IOW, uname will show the last released version of FreeBSD since you upgraded to -STABLE (there's more to it than that, but that's the gist of it). It's just to show a rough idea of "when" in the stable dev process you upgraded. Otherwise, how could people distinguish between "7-STABLE" from 2 years ago and "7-STABLE" from 2 days ago?
Addendum: DD, maybe you're thinking of the security branches, RELENG_X_Y, which is -RELEASE+security fixes+major/uber-important fixes?