Speaking only for myself as an author of a Boost library, maintainer
of many Boost libraries, and contributor to many Boost libraries, as
well as being involved in the Boost release process:
1. Based on my personal knowledge of Boost users, as well as e-mails
to the Boost developers lists (boost@...), and the Boost Owners lists
(boost-owner@...) from users such as:
- @us.af.mil (US Airforce)
- @nasa.gov (NASA)
and others
I would not be in favor of a Boost distribution that requires anything
higher than C++11 for existing libraries. i.e. Not C++17 or even
C++14.
2. Based on first hand accounts of certain users choosing not to
migrate to C++20 because of a silently breaking change in the language
affecting their code (operator== rewriting rules, which has even
broken certain Boost libraries like Rational), I would certainly not
be in favor of changing existing Boost libraries to require C++20 for
anything in an official Boost distribution.
Glen