Stroika itself doesn't depend on C++17. Stroika is versioned, so that the v2.1 branch depends on only C++17 (though if available, supports some c++20 features,

Stroika itself doesn't depend on C++17. Stroika is versioned, so that the v2.1 branch depends on only C++17 (though if available, supports some c++20 features, like operator<=>). The Stroika v3 branch requires C++20 (so requires features like concepts, operator<=>, jthread) in your compiler. Stroika 2.1 is released and stable, and Stroika v3 is in active development.