For your LineaPro hardware to work on the newest version of iOS (9.3.1) you will also need to be running the latest version of the LineaPro firmware on your device.
Follow the step below to update your LineaPro Firmware.
Please note: This must be complete before you upgrade your iDevices to iOS 9.3.1 (or higher).
On your iDevice, navigate to the App Store and install the IPCSupport App.
Once the app has downloaded, open it and select Firmware.
Select Auto Update
Select LINEAPro5 XBPM 5.63.0
This will apply the latest Firmware (you will see a warning message not to interrupt the installation).
You are now free to upgrade the iOS version of your device.