App installation failed - application’s application-identifier entitlement

I am recompiling an old app and getting this error:

"App installation failed - This application’s application-identifier entitlement does not match that of the installed application. These values must match for an upgrade to be allowed."

How to fix it? I know that if I delete the app on the phone, then it will install the fresh one OK. But I have app data I don't want to delete. Also -- what about other users who update, will they be able to?

Thanks