I know other DJI higher end drones have the option in the DJI GO 4 app to do a Gimbal Calibration.  I also know that a Gimbal calibration is possible using additional software and such on the Spark.
Why hasn't DJI included this for the spark in the DJI Go 4 app and do you think they ever will, it would just make sense as it seems completely possible.

I don't think that there will be any new firmware updates for spark....