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