Not sure if it's really what you are looking for, but the C++ Core Guidelines (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines) are what I check when I have to touch a C++ code-base. It precise which parts of C++ are to be used and which are to be avoided according the creators.

cppreference[1] is fairly minimalist, usually up to date and clearly marks which feature came with which standard. It is generally useful for everyday c++ coding.

[1] https://en.cppreference.com/

Full disclosure: I don't work with C++ anymore.

You don't have to keep up with all the stuff it adds. If you actually need a certain thing C++ has added -- that you're unaware of -- you'll naturally find it when you go looking for it.

Otherwise, it's best to just stick with the feature-set that you know. KISS/YAGNI/if it ain't broke, don't fix it (but if it is broke, find a better way). Et other cliches.

I strongly disagree with this. While you can keep using the old stuff, many of the new things will make your code better if you use them. Sure you don't need the new stuff, but the highlights are important. There are also a lot of esoteric things that only a few people will use (but they really need), but you need to keep up just so you can use new features that make your code better.

This repo has a concise summary of new features, if that is the sort of thing you are looking for: https://github.com/AnthonyCalandra/modern-cpp-features