According to the documentation: The base LLVM version was changed between minor versions: - 17.1.2 is based on LLVM17 - 17.1.3 is based on LLVM19 https://www.ibm.com/docs/en/openxl-c-and-cpp-aix/17.1.2?topic=whats-new https://www.ibm.com/docs/en/openxl-c-and-cpp-aix/17.1.3?topic=whats-new Co-authored-by: Hristo Hristov <zingam@outlook.com>