C++17 is a version of the C++ programming language standard, officially released in December 2017. It introduced several new features and improvements, enhancing the language's performance and usability. Key additions include structured bindings, optional types, and parallel algorithms, which help developers write cleaner and more efficient code. This version also improved the standard library with features like filesystem support and enhanced template argument deduction. Overall, C++17 aims to make programming in C++ more intuitive while maintaining the language's powerful capabilities, making it a popular choice for system and application development.