Changelog V5.6:
adaption for patch 1.43
custom sound attenuation config for a realistic sound isolation in the cabin (ETS2 1.43 only!)
new turbo samples
added turbo blowoff-effect at certain rpms
new engine brake sounds
small changes & volume optimizations in all sound tracks

Changelog V5.5:
work with the 1.42 convoy mode. Now other players can also hear the engine sounds
multiple variations of the engine start and stop sounds (depending on compressor on/off, opticruise gearbox/manual gearbox)
slightly reworked compressor sound
small changes in the load/exhaust soundtracks
new turbo sound
new engine brake sound
new blinker sound behaviour
new sounds for applying/disengaging the parking brake
new parking brake apply warning
new manual gearbox + clutch sounds

Credits:
Max2712