Generally speaking, more conservative users will wait at least until the xx.1 point release before switching to that major version, but if you're on the very conservative side you may want to wait until xx.2. However, there are numerous updates even between minor point releases which you could apply if any errata are discovered if you don't mind.
I couldn't find anything about those extensions being enabled by default in 10.4.
10.4 = Versoin 10, Services Pack 4
11.1 = Version 11, Services Pack 1
At least that is how i think of it. Am I missing something? What isn't obvious about it?
I think the number of times I've witnessed discussions over the decades regarding "which version of FreeBSD should I use?" numbers in the hundreds.
10.4 is intended for individuals who are still running 10.x
sheesh.
:D