If your dog is on a walk, or away from the Fi Base, but near an owner who is signed in and running the Fi App, the collar will connect to their mobile device to report your dog's location. See: How Does the Fi Collar Obtain My Dog’s Location?
Since it is crucial to keep the Fi App open or running in the background at all times, if you close the app you'll receive a Fi App Closed Alert to help prevent this from happening:
What Is Force Closing? 🤷♀️
Force closing means you have closed an app on your phone and it is no longer running. Therefore, no data can get to or from the app.
How Does a Force Close Happen?
On an iPhone X or later, swipe up from the Home screen. On an iPhone 8 or earlier, double-click the Home button to show your most recently used apps.
From here, a force close happens if you swipe up on the Fi App, or any app. This closes the app and is no longer showing under open apps. The only time you should force close is if the Fi App is not responsive (re-open after you force close). To keep the Fi App running when you are done viewing, do not swipe up, simply tap away from the app.
Why Shouldn't I Force Close? 🚫
The Fi Collar system has been designed so that we can track your pup at all times seamlessly. This means the Fi Collar needs access to the Fi Base, and Fi App as your pup goes through their daily activities.
If the Fi App is not running in the background, the Fi Collar cannot connect to any owner's mobile when needed.
The Fi App helps extend coverage any time you and your pup are together, and out of range from the Fi Base or Wi-Fi. See: What Is the Best Connection Source for My Dog’s Fi Collar?