More recent standards also fixes several issues with C++11 atomics, like the template definition for store/swap conversions were mis-specified, so they did not

More recent standards also fixes several issues with C++11 atomics, like the template definition for store/swap conversions were mis-specified, so they did not work, and atomics were not defined to be compatible with C11 and now are going to be. So there are further usability improvements that come with the later standards, beyond the initial standardization that C11 brought to the table. It is not like you had needed C11 to get threads either before, but it does make the code clearer and more portable now.