Deprecating classes and function in C++11 [duplicate]

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• C++ mark as deprecated 6 answers

I am working on a project in C++ where I have written a set of new classes which supersedes some other classes with similar functionality. I therefore want to deprecate the old classes and all methods within it. I've found you can do [[deprecated]] or [[deprecated](reason for deprecation)] but this only for C++14. I'm using C++11 but surely deprecating something its a new thing that only the latest C++ versions can do?

Am I missing something or would I have to upgrade my project to be C++14 (assuming I have a compiler that is capable)?