During October 2025, Kdn contributed to the NixOS/nixpkgs repository by implementing CMake 4 compatibility patches for the arrow-cpp and ceph packages. Focusing on build system management and package management, Kdn addressed emerging compatibility issues as the toolchain evolved, ensuring that downstream users could upgrade to CMake 4 without disruption. The work involved updating cpp_redis and related components, coordinating cross-repository patches, and maintaining build integrity throughout the process. Using Nix and CMake, Kdn documented all changes and linked them to the relevant issue for traceability. The contribution demonstrated careful attention to stability and long-term maintainability in complex build environments.