Clarify uuid requirement for app account token

content/docs/ios/sdk-reference/identify.mdx

@@ -26,6 +26,12 @@ public func identify(
 | `options` | `IdentityOptions?` | Optional configuration for identity behavior. Set `restorePaywallAssignments` to `true` to wait for paywall assignments from the server. Use only in advanced cases where users frequently switch accounts. Defaults to `nil`. |
 </ParamTable>
 
+<Warning>
+  `appAccountToken` must be a UUID to be accepted by StoreKit.
+
+  If the `userId` you pass to `identify` is not a valid UUID string, StoreKit will not accept it for `appAccountToken` and the SDK will fall back to the anonymous alias UUID. This can cause the identifier in App Store Server Notifications to differ from the `userId` you passed. See Apple's docs: [appAccountToken](https://developer.apple.com/documentation/appstoreserverapi/appaccounttoken).
+</Warning>
+
 ## Returns / State
 This function returns `Void`. After calling, [`isLoggedIn`](/ios/sdk-reference/userId) will return `true` and [`userId`](/ios/sdk-reference/userId) will return the provided user ID.
 

content/shared/user-management/identity-management.mdx

@@ -113,6 +113,34 @@ On iOS, Superwall always supplies an [`appAccountToken`](https://developer.apple
 |----------|----------------------------------|
 | You’ve called `Superwall.shared.identify(userId:)` | The exact `userId` you passed |
 | You *haven’t* called `identify` yet | The UUID automatically generated for the anonymous user (the **alias ID**), **without** the `$SuperwallAlias:` prefix |
+| You passed a non‑UUID `userId` to `identify` | StoreKit rejects it; Superwall falls back to the alias UUID |
 
-Because the SDK falls back to the alias UUID, purchase notifications sent to your server always include a stable, unique identifier—even before the user signs in.  
-Make sure any `userId` you pass to `identify` is a valid UUID string, as Apple requires `appAccountToken` values to follow the UUID format.
+Because the SDK falls back to the alias UUID, purchase notifications sent to your server always include a stable, unique identifier—even before the user signs in.
+
+:::ios
+<Warning>
+  `appAccountToken` must be a UUID to be accepted by StoreKit.
+
+  If the `userId` you pass to `identify` is not a valid UUID string, StoreKit will not accept it for `appAccountToken` and the SDK will fall back to the anonymous alias UUID. This can cause the identifier in App Store Server Notifications to differ from the `userId` you passed. See Apple's docs: [appAccountToken](https://developer.apple.com/documentation/appstoreserverapi/appaccounttoken).
+</Warning>
+:::
+:::flutter
+<Warning>
+  On iOS, `appAccountToken` must be a UUID to be accepted by StoreKit.
+
+  If the `userId` you pass to `identify` is not a valid UUID string, StoreKit will not accept it for `appAccountToken` and the SDK will fall back to the anonymous alias UUID. This can cause the identifier in App Store Server Notifications to differ from the `userId` you passed. See Apple's docs: [appAccountToken](https://developer.apple.com/documentation/appstoreserverapi/appaccounttoken).
+</Warning>
+:::
+:::expo
+<Warning>
+  On iOS, `appAccountToken` must be a UUID to be accepted by StoreKit.
+
+  If the `userId` you pass to `identify` is not a valid UUID string, StoreKit will not accept it for `appAccountToken` and the SDK will fall back to the anonymous alias UUID. This can cause the identifier in App Store Server Notifications to differ from the `userId` you passed. See Apple's docs: [appAccountToken](https://developer.apple.com/documentation/appstoreserverapi/appaccounttoken).
+</Warning>
+:::
+
+```swift
+// Generate and use a UUID user ID in Swift
+let userId = UUID().uuidString
+Superwall.shared.identify(userId: userId)
+```