Deutsche Bahn has now released it DB Navigator app in Windows 10 Store. The app comes with the ability to book tickets too apart from seeing travel information. As per the description, app is still in Beta and will be updated frequently on the basis of feedback from users.
For Windows users it is now also possible to make bookings in addition to travel information. The ticket can be stored offline and is always available. Both the available composite tickets (SH fare is not available, will recommend a booking via bahn.de ), as well as the regional offers, such as country-ticket and cross-country through-ticket can be booked in the Windows version. The “Favorites” feature has also been integrated into the Windows Mobile system. This allows your connections to be stored and are ready for immediate retrieval. Please note that tickets and reservations only on bahn.de can be exchanged and canceled.