Move Base Flex (MBF) is a highly flexible, modular, map independent, open-source navigation framework for ROS. MBF provides modular actions to execute plugins for path planning, motion control, and recovery. External executives can use these action to allow smart and highly flexible navigation strategies, which can be intertwined with other robotics applications. Some companies have successfully deployed MBF at customer facilities to control robots in highly dynamic environments. We demarcate MBF against the well known move base, present the architecture, different application and deployment approaches, including how MBF can be used with different executives to perform complex navigation tasks interleaved with other robot operations. Furthermore, the ongoing latest advancements of MBF are presented.