It is just standard boilerplate. There are saying that the system that warns you automatically if there is a change or a cancellation is not working. So they are reminding you that it is your responsibility to proactively check shortly before your travel date. This is anyway something you always should do. Train travel is not like air travel. Think of it as a fast subway…
You have a ticket, and this allows you to travel. A change in schedule, or a cancellation does not invalidate your ticket. If it does indeed turn out that the train you booked is not running you just use your ticket on another train. Go the FrecciaDesk at the had of the tracks in Milano in that case to have your reservation changed.