ktchong: Again, you are confused by the different between platforms and vendors.
iOS is a platform, not a vendor.
Okay.
Let say a developer has already made an update/patch for an Android app and uploaded it onto Google Play. That means an update/patch for the Android app is already available. So if it's on Google Play, then it really should be on Amazon Appstore as well. Amazon, as a vendor that wants to compete with Google Play and grab market share from Google Play, should pay attention to those updates and patches. Amazon - as a competing vendor - should make those developers upload those updates/patches that are available on Google Play onto its Amazon Appstore. It is NOT my responsibility to contact those developers - there could be hundreds or thousands of them - and urge them to upload the updates/patches to Amazon. Amazon does not pay me to upkeep its apps. Amazon, as a vendor that wants to compete with Google Play, would have to do it. However, Amazon does not. The consequences is customers (like me) would stay away from buying any app from Amazon because we know apps on Amazon would never get updated/patched. It is not my problem - because I can easily just go to the competing vendor. It is an Amazon's problem because Amazon loses sales, loses business, and loses market share because of it.
It is STILL not up to Amazon to update their apps. None of the stores have a clause that says the apps must be updated to its latest version. That's for one. Secondly, you forgot that the Google Play version of an Android app might include integration with GOOGLE services, and likely replacing them with AMAZON services or updating them while integrating new features with AMAZON services is such a big big big time wasting problem for developers. Plus what is the Amazon Appstore's intended audience for? That's right, the Kindle and Fire devices. They don't have Google at all, and their Android is pretty much a radical re-doing of Google's, that you'd almost feel like you're not using Android. It is again the developer's problem. Blame them for being lazy.
On the other hand, just because a developer has made an update/patch for an iOS app does not mean an update/patch is available for the Android version. The update/patch could be for some problems that are specific to the iOS platform. Often the same apps are not even completely the same on iOS and Android: they may have slightly different GUI, different functionalities, different contents, etc. It's just like you do not expect the PC version and the console version of game to have the same version number.
Often the iOS version has more features than the Android versions in apps which favor iOS updates, and these features are far from being impossible on Android. iOS users get more features on their iOS update favored app than on Google Play, yet none complain that Google Play has outdated apps. But they complain that the developer left an app without an update for ages. That is it. The developer is responsible for the app. It should be the developer's reputation that is being at stake, NOT the distributor.
Also, your Knights of Pen and Paper is NOT the Deluxier version. Which means it does NOT include the IAP and expanded contents. That's the whole point to begin with.
BTW. I've just noticed something I'd missed earlier.... the Amazon Underground version of the your so-called "Actually Free" Knights of Pen and Paper +1. The Underground "free" edition does NOT include the Haunted Fall expansion (and its respective IAP contents.) Neither does your Humble edition. The PC Deluxier edition, which is all-inclusive, does... so, checkmate again?
Both Humble Bundle and Amazon Underground editions do include the Haunted Fall expansion. How do I know? Whenever I start the game, the "Haunted Fall DLC" icon pretty much replaces the logo of the game. And I noticed this with the Humble Bundle version and the Amazon Underground version. Checkmate.
Let's not forget my original point: the PC versions of a game is (generally) superior to the Android version - because (a) the PC versions (generally) do not have the IAP that are in the Android version, the IAP contents are already included in the base games on the PC, or (b) the PC often has an all-inclusive "Deluxe" version of the game that already includes all the IAP contents, while Android often does not offer that all-inclusive deluxe version.
And my original point is as follows: while you're complaining that the IAP is separate than the base game (a very very VERY minor problem), I complain that PC games on certain services more often than not imploy DRM. Which means that if the circumstances align to the worst, boom, none of my games can be played. WHAT'S BETTER: Buying the whole game and losing it all when you have to go offline, or buying the base game and keeping it whether you are online or offline? If I have a chance to lose the game, would rather have even a quarter of it in my control instead.