> C++20 is just a new version of the C++ standard. and per ISO rules, older versions are withdrawn (as can be confirmed for C++ here: https://www.iso.org/stand

> C++20 is just a new version of the C++ standard. and per ISO rules, older versions are withdrawn (as can be confirmed for C++ here: https://www.iso.org/standard/79358.html https://www.iso.org/standard/79358.html) and not to be used anymore: https://www.iso.org/files/live/sites/isoorg/files/store/en/PUB100413.pdf https://www.iso.org/files/live/sites/isoorg/files/store/en/P... Other reasons why a committee may decide to propose a standard for withdrawal include the following : ▸ ▸ the standard does not reflect current practice or research ▸ ▸ it is not suitable for new and existing applications (products, systems or processes) ▸ ▸ it is not compatible with current views and expectations regarding quality, safety and the environment