I have a current paid app and I've considered making it a freemium app instead. I would like all the current users who own the game to have all the freemium features unlocked while new users will have to purchase areas of the game to unlock it. Does anyone have experience with this and how did you go about it? The only solution I've seen is doing some kind of update that sets a preference that can be checked later on but that seems hackish and not 100% foolproof (for instance if you delete the game or don't happen to play the game after the update, you'll have to pay again). Though maybe that is the best way
Why not just release a new version of the game that is free with the IAPs and update (so those users get all that content) then remove the paid version from the app store?
Mostly because my game has Gamecenter Leaderboards and Achievements and I would hate to lose all the old high scores.
I don't think that is a strong enough reason. There are plenty of games with regular and HD versions that have separate leaderboards. Have separate leaderboards for paid vs. freemium is probably a good thing anyway. Then the paid people won't be complaining that the freemium people bought their way to the top (if that is even possible in your game).
+1, yes this is the best solution (or the less worst if you see what I mean) -1 that is a terrible idea. Keep both version.
The only problem I see with having two seperate versions is that there's a good chance that total combined value of all of the IAPs might be well and truly more expensive than the paid version of the app. So if the app spreads via word of mouth people might tell their friends to get the paid version with the IAPs included, and that could potentially limit the revenue. But, that all depends on how much IAPs there are, how likely it is that people will buy them etc.
Well, the source of that problem would be you...I mean, there's a way to make both apps worth the same amount of money!