Märklin Mobile Station 2
Märklin has released a service update for the Mobile Station 2 (this concerns the Trix Mobile Station 2 as well). The update fixes an issue with the speed regulation that controls the accelleration and deacceleration of locomotives. The issue causes the train to jump in speed when turning the speed up, down or changing direction.
You can download the update through the Central Station 2 connected to the internet.
Simply update the Central Station 2 software from the internet, and you will receive the new software for your Mobile Station 2. The Central Station 2 will then update the Mobile Station 2s that you connect to it.
If you have a Mobile Station 2 with the new software, it can update other Mobile Station 2s as well by connecting both of them to a railbox (Märklin #60113).