http://www.boost.org/users/history/version_1_56_0.html
Just a quick warning, if we consider upgrading. There seems to be a problem with file_lock on Win32, which I can fix by just commenting out #include <boost/interprocess/sync/file_lock.hpp> and the file_lock.
I also opened an upstream ticket: https://svn.boost.org/trac/boost/ticket/10325