Fails to compile with clang11

[SpaceIm]

README claims that clang11 is supported, but when I try the basic example with clang11 on Linux, compilation fails:

In file included from /home/conan/w/prod/BuildSingleReference/conan-center-index/recipes/reactiveplusplus/all/test_package/test_package.cpp:1:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/rpp.hpp:13:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/observables.hpp:19:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/observables/specific_observable.hpp:14:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/observables/fwd.hpp:13:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/subscribers/fwd.hpp:13:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/observers/constraints.hpp:13:
In file included from /home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/observers/fwd.hpp:13:
/home/conan/w/prod/BuildSingleReference/.conan/data/reactiveplusplus/0.1.2/_/_/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/rpp/utils/constraints.hpp:13:10: fatal error: 'concepts' file not found
#include <concepts>

Could you provide exact minimum supported versions of major compilers please (gcc, clang, msvc, apple-clang, though I guess apple-clang is not supported at all since it fails to compile even with latest version apple-clang 14 due to lack of std::ranges support)?