On your iPhone device, there is a feature that always keeps your apps up to date with the latest versions of the app, including the Mileage Book app.
To activate this function, simply follow the steps below:
1. Select Settings
2. Select iTunes & App Store
3. Under the “automatic downloads”, look for “updates” and make sure to toggle it ON
4. Next, you have the opportunity to specify if your iPhone should use mobile data to keep your apps up to date. This is enabled under "Use Mobile data"
If this is not enabled, the automatic update of apps will only be available when your iPhone is connected to a wireless wifi network.
You have now enabled automatic updating of apps, thus ensuring that your Mileage Book app is always kept up to date with the latest version.