C++11 is a major update to the C++ programming language, officially released in 2011. It introduced several new features aimed at improving performance, usability, and support for modern programming practices. Key additions include auto type inference, nullptr for null pointer representation, and lambda expressions for writing inline functions. This version also enhanced the Standard Template Library (STL) with new containers and algorithms, as well as introduced smart pointers for better memory management. Overall, C++11 aimed to make C++ more efficient and easier to use, while maintaining its powerful capabilities for system-level programming.