There is currently a pull request for cctbx that will update Boost to 1.70 (https://github.com/cctbx/cctbx_project/pull/409). The update enables support for Python 3.7 and 3.8. The plan is to merge this next Friday, May 8, at 3 pm Pacific. After merging, developers should delete the build/lib/*boost* files and build/boost directory so that any remnants of the old Boost are removed and then rebuild.

Let me know if you have any questions. Thanks!