Since you might integrate us when your app is already on the App Store, we would need to know whether your app update would be an actual UPDATE or an INSTALL. Have a logic in place to differentiate between the two, and use the methods below to let the SDK know about the same:
//For Fresh Install of App
MoEngage.sharedInstance().appStatus(INSTALL)
// For Existing user who has updated the app
MoEngage.sharedInstance().appStatus(UPDATE)
//For Fresh Install of App
[[MoEngage sharedInstance]appStatus:INSTALL];
// For Existing user who has updated the app
[[MoEngage sharedInstance]appStatus:UPDATE];