An in app purchase is available to give the app a multi device capability by enabling a Synchronization to it. Below are the steps to give it this capability

1.After registering in the application and having first in app purchased the balance of the modules, then in app purchase the Synchronization capability.

2.Install the app on the 2nd device you want to use. As you were registered as the user on an online database, the same login details need to be used to login on the 2nd device.

3.Following entering data on the 1st device, go to Settings on the app and push the Synchronise button.

4.Once that is done, login to the 2nd device and press synchronization button and you will see that the data on the app has been updated on both devices.

Just another WordPress site