On Fri, Nov 9, 2018 at 12:54 AM Heng Zhou via Boost-users <boost-users@lists.boost.org> wrote:
Hi,

I installed Boost 1.68.0 recently from Windows x64 pre-compiled binary "boost_1_68_0-msvc-14.0-64.exe" downloaded from https://sourceforge.net/projects/boost/files/boost-binaries/1.68.0/. Then, I noticed that this version of Boost contains only python 3.7 library because the filenames under C:\local\boost_1_68_0\lib64-msvc-14.0 are only boost_python37-vc140-mt-.... This caused errors from building a third-party library which tries to link Boost python 2.7 library (i.e., tries to find file boost_python27-vc140-mt-...) . So what is matter? Does Boost decide to stop supporting python 2.7 since version 1.68.0, or is Boost python 2.7 library located somewhere else using some hard-to-recognize filename? I'm using Windows 10, VS2015 and have only python 2.7 installed. Thank you for your help with this issue.

That is by design. On windows boost can only support one version of python at a time. Since python 2.x is end-of-life and only going to be supported for another 14 months I thought it would be better to default to python 3 going forward. It was discussed in this thread:
https://lists.boost.org/Archives/boost/2018/07/242443.php

You can still use other versions of python with boost, but you'll just have to build the boost::python library yourself.
https://www.boost.org/doc/libs/1_68_0/more/getting_started/windows.html#prepare-to-use-a-boost-library-binary

Tom