Boost release 1.58.0 beta 1 is now available from SourceForge

See http://sourceforge.net/projects/boost/files/boost/1.58.0.beta.1/

This release contains three new libraries:

• Endian: Types and conversion functions for correct byte ordering and more regardless of processor endianness.

• Sort: includes spreadsort, a general-case hybrid radix sort that is faster than O(n*log(n))

• WinAPI: 

For details of what's in the release, see http://www.boost.org/users/history/version_1_58_0.html. 
Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files.