You need to update it once.
You can select the mercedes 1998 e320, then instead of selecting ISS you can select the "petrol" then select engines type as M112.942 (3.2 L), the next selection should say ME-SFI as the engine controller. Then press the rightmost bottom (with engine icon) , and then a new window opens, at leftmost top shows if there are any faults , the next icon below clears the faults (do not clear anything if no faults, else it will reset your emissions readiness). The icon below allows you obtain the data from the ECU.
Make sure the ignition key is in "run" position.
You can do the same thing for the transmission. Make sure you select the gearbox, not the EWS (shifter) The shifter will not provide any data because for 1998 e320 it is not a reachable module.
DO NOT use anything other than 1998 (if your car is 1998) when testing the gearbox. Because the newer facelift models have a different TCM (EGS52) and yours is an EGS51.
For bluetooth, you need to go to the panel where you updated the firmware, and select the connection type BT and usb (2nd selection out of 3, I think) and then you need to TEST the connection which will then register in the tester.