Coost v4.0.0 is a major release that raises the minimum C++ standard to C++17, removes high-maintenance modules (dynamic libraries, hooks, HTTP/SSL components, fastring, fastream, and coroutine channels), and adds support for Windows ARM64 and FreeBSD platforms. Core components have been optimized and consolidated into the co namespace with improved APIs and performance improvements across logging, closures, synchronization primitives, and other utilities.