Converting Payed App to Freemium

I just converted my App to Freemium, but the method is used to give user, that bought the App before it was free, access to the paid futures seems not to be working.

I am getting the original Purchase Date from the AppTransaction (https://developer.apple.com/documentation/storekit/apptransaction/originalpurchasedate) and comparing that to a set date where the App Model changed. In Test Flight this is working without any Problems but on the Live System, users that have purchased the App do not get access!

let shared = try await AppTransaction.refresh()
                        if case .verified(let appTransaction) = shared {
               result(appTransaction.originalPurchaseDate.ISO8601Format()).
                        }

I am using flutter to develop the App and the result()... send the string back to the flutter side.

Here is the code of the Flutter side:

  Future<void> restorePurchases() async {
    SubscriptionProvider().updatePayment(PurchaseStatus.pending);
    await InAppPurchase.instance.restorePurchases();
 
    if (Platform.isIOS) {
      DateTime changedToFreemium = DateTime.utc(2025, 4, 7, 11, 0, 0);
      String? purchaseDateRaw = await IosFlutterChannel().getOriginalPurchaseDate();
      if (kDebugMode) {
        print("Purchase Date Raw: $purchaseDateRaw");
      }
      if (purchaseDateRaw != null) {
        DateTime purchaseDate = DateTime.parse(purchaseDateRaw);
        if (purchaseDate.isBefore(changedToFreemium)) {
          if (kDebugMode) {
            print("Restoring legacy purchases");
          }
          SubscriptionProvider().update(true, SubscriptionStatus.active, SubscriptionType.fs_lifetime);
        } else {
          if (kDebugMode) {
            print("Not restoring legacy purchases");
          }
        }
      }
    }
    SubscriptionProvider().updatePayment(PurchaseStatus.purchased);
  }

Console Log when running in Test Environment:

flutter: Purchase Date Raw: 2013-08-01T07:00:00Z
flutter: Restoring legacy purchases

Thanks!