I think we can; let’s bump CMake to do C++17. This probably involves some new warnings, so the MR might be larger. Documentation about minimum compilers needs updated too. mindeps might need a new devtoolset installed too.
Note that clang-format is currently set to using Cpp11. Updating that may involve some reformatting; we should try this without updating clang-format first; if we need to update, it’s a bit more involved (but hopefully doesn’t change too much to inhibit nice backporting; the main reason pre-branch formatting is vastly preferred).