PC Disable "objective Complete" Message And That *ding* Sound?

Hi,
is it possible to disable that "Objective complete" message and that *ding* sound?
They are really immersion breaking. I know you don't see the "Objective complete" message when you disable the HUD but you still get the sound that is also immersion breaking.

So is there any way to disable that?
A .ini setting?
A mod?
Something else?

 

My menu is in German but you can count ;-)
For the sound: put the one after UI to off
For the message go to player help and turn off the 4th option
I think this should do it.

 

My go, vielen dank. I have been looking for this for a long time!!!

 

Thanks. But while this may disable the notification on new routes, in typical DTG fashion (inconsistency as always) it does not deactivate the "Objective Complete" Message in older routes (pre-TSW 6).
Just awful