Mobile offline - will be local data deleted on user sign out?

Hello. We are planning to build an offline mobile application, comparing to online it have multiple limitations. So one of the questions is:   If user will sign out, will all data that is not synchronized will be deleted? And how to avoid this if yes?   Thank you in advance.
1 answers

Yes, the data is deleted when you logout. You will lose all data that has not been synchronized.

As far as I know, there is no way to avoid data being deleted. 

The workaround I implemented when I faced this issue, is that I show the user a large pop-up when they log-out, which tells them they will lose their data if they continue. I provide them with three buttons in the pop-up: synchronize, log-out, and cancel.