Boost release 1.72.0 beta 1 rc2 is now available at: https://dl.bintray.com/boostorg/beta/1.72.0.beta.1.rc2/source/ The release notes are not yet available. The updated documentation is not yet available. [ They will be available in a day or two. ] The SHA256 checksums are as follows: 5a6b5cbd27b8ca0c7741b715e022a3bf05aecbb1e73dc72dd82eef9622374bd5 ./boost_1_72_0_b1_rc2.7z 6c85a7aed198757f5e4be66a971ae90a25c4ce32703fecfb5bb19019bd80947c ./boost_1_72_0_b1_rc2.tar.bz2 be4a3fdaa84d5a8b25863651043308e02645f3fbf772b7623ee6462fb1dbad09 ./boost_1_72_0_b1_rc2.tar.gz 95181a5f3de0078b8fc031f63a4dc8be4d70b7d3d5cde3b266d2cd98bd4b61b0 ./boost_1_72_0_b1_rc2.zip Changes since RC1: * Fix Boost.IOStreams to allow compilation on Mac OS w/LZMA support. Please download the beta release candidate, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team