Boost release 1.91.0 beta 1 is now available at: https://archives.boost.io/beta/1.91.0.beta1/source/ The SHA256 checksums are: b8e78a226d2c0bd6ad4346254988dc2af15c0ae569d974e4da09e7dd0f338980 boost_1_91_0_b1.zip d1eb15102b3379bff874894dd0c39d25a85c9c41147a2dd25215602b911125db boost_1_91_0_b1.tar.bz2 866a39f4b6b1591c04bbb7d9c70ed241a794162512df0fa2ef79374b774354a3 boost_1_91_0_b1.7z 1194fb011943b4425cc6e15f3ee7272ae9c8331938c7d1bac8767850463c2e84 boost_1_91_0_b1.tar.gz Please try the beta and report any problems you encounter. Thanks to everyone who contributed to the release. -- The release managers