For a limited time the app will run in the background, however with the next releases of both the free and Pro versions of the app unfortunately background running has had to be removed.

This is due to a policy update by Google who have applied much firmer restrictions on how apps access the device location in the background. While I believe that DigiHUD has a valid case for accessing location in the background (calculate average speed, recording routes, maintaining statistics etc.) version 8 and later of Android now restricts the frequency it can do so. This effectively kills the accuracy of the app as a real-time speedometer, which is not something I can live with. Whilst testing the latest update to the app I’ve found background running to be very inaccurate, with location updates stopping within a short period of time.

To quote Google’s latest Developer blog update:

If background location access is essential for your app, keep in mind that Android preserves device battery life by setting background location limits on devices that run Android 8.0 (API level 26) and higher. On these versions of Android, if your app is running in the background, it can receive location updates only a few times each hour.

Read more from Google on the latest restrictions to accessing location in the background:

https://support.google.com/googleplay/android-developer/answer/9799150