It took me a while to find the time to upgrade to FreeRTOS V7.4.2, but finally it is done :-). What caused me to move from V7.2 to V7.4 is a low power application on the FRDM-KL25Z board. V7.4 comes with two major new features: Queue Sets and Tickles Idle Mode (see this article). The last one if of interest here.
FreeRTOS runs an IDLE task. This one runs when there is no other active task. That task calls an optional Idle task hook which is a perfect place to put the microcontroller into low power mode: