Thanks for your answer. Really nice to see StoreKit2 solves it this way. While we are at this subject, would you mind to explain me how I can have my app's icon displayed on the payment screen? Whenever I add a product to the StoreKit's payment queue, all the details presented in the payment sheet are good, but the app icon is missing (it is this default white development icon with a grid and circles). Please note that my app also doesn't have an icon in App Store Connect (it also has the default one) and I cannot find a way to change it.

I am not sure. I just reproduced it on my iPhone XR by running the code in Xcode. This message was logged in the Xcode console: Message from debugger: Terminated due to signal 9 Usually, when the app crashes, it drops into the debugger at the line where the error occurred. This is not the case now. I looked into Settings -> Analytics & Improvements and there is no entry from today for my app. But I am not sure if the apps ran from Xcode dump crash reports there. Do I need to deploy the app to TestFlight and reproduce it there so that a crash report is generated? Or can I somehow have this crash report generated while running the app in Xcode? Will go through the resource in the link you provided, but I'd appreciate some hints on how to investigate it when running the app in Xcode. Thanks!

I was following the instructions from Create a Crash Report While Debugging, which say I should do Debug -> Detach and it turned out that it helped. After doing that I can change the app language in Settings and when I navigate back the app restarts nicely without any freeze. I guess it was actually debugger that was killing the app, because upon launch to Settings I was leaving my app and then when navigating back, the debugger was in some incorrect state...

Thank you for your answer @eskimo. Please see my update below.

Again submitted an answer as a comment by accident. Please see my answer with better formatting below.

Thank you for the quick answer! That seems to be a good approach for my app as it is not that popular so I doubt it will hit the limit of 15000 codes per quarter. The configurability of Offer codes looks good, but I don't really need redemptions via URL—everything is done in-app. I wish there was an easier solution so that the user wouldn't have to enter any code and that I could just configure it all together as an Introductory offer, but I guess I will have to go with that approach. You mentioned "Pay as you go Offer Code" that allows redemption of Introductory offers. Do "Pay up front Offer Code" also allow redemption of Introductory offers? My current subscriptions are configured as 1-week trial + Pay up front for the whole period. And just in case, let's say I estimate that I will sell more than 15000 subscriptions in a given quarter and I wanted to implement that logic, what approach would be appropriate in that case?

My bad, it was a typo. 150,000 per quarter should be more than enough for my app at the current stage. I also thought about auto-populating the code for the user, but I thought about doing that within the app. Following the provided link, it reads "Redeemable through a direct URL or within your app on iOS 14.1 or iPadOS 14 or later." so I'd be interested in "within the app". That's just better user experience for the user and better conversion for me. I don't understand would it be necessary to take the user out of my app? Can't I just add the offer code to the SKPayment? Assuming I will not hit the limit of 150,000 per quarter, I would implement it as follows: add logic for showing reduced prices on the subscription screen and auto-populate the offer code for a limited period of time, e.g. from the beginning of June till the end of September. After that, I'd go back to showing the regular pricing and the offer code would not be attached anymore or would simply expire. The 1-week free trial IntroOffer would work the same as before. Is that a feasible solution given what StoreKit can offer? I've updated my app's deployment target to iOS 15 so I can use StoreKit2 if needed.