[@henningw](https://github.com/henningw) I want to use C17 features in my kamailio module :)
I think you can create a new module with whatever standard you want if you set the standard in it's own module `CMakeLists.txt`. CMake will respect the standard set only for that module and whatever is included in that file.
Bear in mind though, that the compiler used must support the version, and if you want it packaged, we are using the OS package-distributed `gcc` or `clang` that might or might not support it fully on that OS version.