I'm using,
Z:\>rsync.exe --version
rsync version 3.0.9 protocol version 31 (os2-perms)
Copyright (C) 1996-2011 by Andrew Tridgell, Wayne Davison, and others.
Web site: http://rsync.samba.org/
Built by Steven H. Levine Dec 21 2012 10:43:12
Built with GCC 4.4.7
Capabilities:
64-bit files, 64-bit inums, 32-bit timestamps, 64-bit long ints,
socketpairs, hardlinks, symlinks, no IPv6, batchfiles, inplace,
append, no ACLs, xattrs, iconv, symtimes
rsync comes with ABSOLUTELY NO WARRANTY. This is free software, and you
are welcome to redistribute it under certain conditions. See the GNU
General Public Licence for details.
Note the built by Steven H. Levine part along with (os2-perms).
I'd assume the newer one is similar as Steven has been maintaining it.