How to determine the date an app is installed or used for the first time?

Question

I\'m planning on opening up an in app store and I\'d like to give existing users some of the items for free.

I thought of releasing an update which would store some

Answer 1

I'd recommend simply setting a date on first launch and storing it in NSUserDefaults. Look for the date on launch, if it's not there, set it. If it is, do some date comparison and handle the rest according to your plan.