Zlib version in FreeBSD - 3 releases behind?

[KrisUniverse]

The Zlib baked into FreeBSD is Zlib 1.2.4 even on 9.1R.

However, Zlib has gone to 1.2.7 sometime ago after stepping through 1.2.5, 1.2.6 and 1.2.7 with bug fixes.

Is there any reason for not using Zlib 1.2.7?

Thanks.
Kris