Information on regional trains
The digital regional ticket:
1. is nominative, personal and non-transferable;

2. must be validated with the check-in function after midnight on the day of travel and before the scheduled departure of the train selected at the time of purchase;

3. is valid only for the train(s) for which you have checked in;

4. must be displayed on a electronic support (PC, tablet, smartphone) that shows the barcode to be presented together with a valid identification document, upon any request from the ticket inspectors – if either is lacking, the passenger will be considered as being without a ticket and shall be duly charged in accordance with the regulations in force;

5. date and time can be changed up to 11:59 pm on the day prior to the date of travel, unless otherwise established by regional regulations;

6. time can be changed before check-in up to 11:59 pm on the day of travel, unless otherwise established by regional regulations;

7. no change of name is permitted.

https://www.trenitalia.com/it/informazioni/cerca_e_modificailbiglietto.html

https://www.trenitalia.com/it/treni_regionali/nuovo-biglietto-digitale-regionale.html

wynika, że przychylili nieba podróżującym i wprowadzili jakiś nowy system (...). Napisz później jak to załatwiłaś.

A poza tym nie kupujcie biletów na regionalne w apce. Po co? Więcej czasu i zachodu z tym niż kupno w automacie, a korzyść żadna.