Correct: You do have side sensors mounted on the Drone but now they work in cooperation with the other sensors as an omnidirectional avoidance system. As the tech for these sensors has improved it is no longer necessary to give the side mounted sensors a "specific purpose".
So while the side sensors may not receive firmware just for them, The future updates, and this one, certainly send info to the mounted sensors as part of a unit of front,back, and side, that are now one omnidirectional sensor.