Did you mean C11 there or C++11? I'm not sure why C11 is relevant in a discussion about C++. MSVC's support of C has been abysmal for ages, but this has no reflection on its C++ support. Of which it definitely supports all of C++11. And 14. And 17. And even complete support for C++20
For C++20, GCC is "only" missing module support, but otherwise supports everything else. Clang is lagging behind, though.