a question about binutils snapshot & release versions

[Kamble, Nitin A]

Hi binutils developers,
  I have a question about release version of binutils. I need to choose right version of binutils for the yoctoproject.org. And I am bit confused by versioning scheme out there.

As per this webpage: http://www.gnu.org/software/binutils/, The latest release of GNU binutils is 2.21.
But I see snapshot images over here ftp://sourceware.org/pub/binutils/snapshots up to version 2.22.51.

So aren't the snapshot images official version of binutils? I was thinking the 2.22.51 should be the latest version, but it is not.

Can somebody please explain me this versioning scheme, and when to use the latest snapshot and when the latest released version?

Thank you,
Nitin