Codeforces is one of few platforms which support C++20. Some others are using C++17 like AtCoder and CodeChef. Topcoder and many classical OJ such as POJ is still using C++11 if I recall correctly. And for Java I haven't seen one that supports Java18.

So here's the question. I think update the compilers is rather a simple thing. Well, at least for my PC. Is there any technical issue on updating the compilers or will it cause some trouble?

Sorry, I don't have many knowledge on this, but it really confused me because it makes me to follow different standard when solving problems on different OJ...