Auto Increment Based on Other Pick list status in Cases Module

Auto Increment Based on Other Pick list status in Cases Module

Dear Team, 

In the Cases Module, we like to set auto increment field when status of case is closed. we have configured the custom function for the mobile application. However as mobile supports offline mode, sometimes these function is not working and others also not updating in the cases. 

Please suggest us the solution to apply in the mobile app considering the offline functionality. Is there any process where we can disable offline functionality in the app.