"Protect" app: Free to full version via InApp purchase? Market license verification? Or useless?

Question

Now I've nearly finished my first app and I wanted to have two versions of it, one free (with ads and a little less functionality) and one full/paid version.

I know that you can not completely prevent apps from being cracked/distributed, but anyway, I'm currenlty having some thoughts about what the best method would be to release the app.

1) Both full and light versions in the store with no additional checks

2) Full version with Google Market license check integrated... Does this really bring any "security"? I've read that this protection has been cracked and therefore is pretty useless?

3) Have the light version and convert it via InApp purchase to the full version? Currently I have no idea on how to implement InApp billing and how to check whether a user paid inApp to release the full functionality and... of course there are also ways around that, right?

How would you do it? Do you try to prevent your app from being illegally shared, or do you think it's not worth the effort, as any protection can be removed (and then it's shared anyway)?

Just gathering some thoughts :)

Answer 1

I have been through the same thought process and settled on option 3 for new apps.

My reasoning is as follows;

With option 1 you have two apps to maintain, users have to do a uninstall of your trial version and you have the problem of migrating data between the two versions.

Option 2 has all the problems of option 1 plus the headache of implementation.

Option 3 you have the benefit of only one codebase to maintain, users can quickly and easily upgrade with all their data intact and you have higher download stats/ratings for the one app rather than two.

Implementing it has got a lot easier with the version 3 of the billing library. I followed the sample from Google here and got a simple remove the ad's with IAB within a couple of hours.

Answer 2

I personally think that an In app purchase is the most secure way to stop people from getting free paid versions of your app, because when someone inevitably (if your app is popular) release an apk file of your app on the internet, it is just the free version.