What does it mean to initialize a string like "std::string mystring{""};". Is it new feature of C++ 11 or 14?

I am new to C++ 11 & 14. In my new role I saw a code where string was initialized (below) and I do not know what is this new way called and where to read about it. Can some one tell what is it called and how does it work. Regards.

std::string mystring{""};