If you find that the odometer in your Mileage Book remains unchanged, you probably have a trip in the future. This means, that you have a trip, which is registered on a later date than the current date.
An example of this could be the following:
Peter can see in his Mileage Book app that he has driven 3450 km, but finds that every time he starts a new trip and has to enter the odometer value, it will be constantly stay on 1820 km. Peter decides to open the Book tab in the Mileage Book app, where he selects the last month. Here he sees that he has a trip on 04-10-2017, but the current date is d. 12-09-2017.
Peter decides to delete this trip, solving the problem he experienced with the odometer value. It turned out that the odometer of the trip stood at 1820 km, and since the Mileage Book app always dictates the odometer value from the last ''driven'' trip, the odometer value was stuck at 1820 km.
The Mileage Book app will always take the odometer value from the last ''driven'' trip, which means that if you create a trip in the future, the Mileage Book app will use the odometer value from this trip.