The C++20 standard has been ratified. When can we expect support?
I am not able to give you an ETA, I can suggest you to follow https://jira.sonarsource.com/browse/MMF-2138. C++20 support is still partial in all compilers, we use Clang frontend as core of our analyzer and it still has partial support for C++20.
Let me point you to our latest C++ related announcement.