In-App Purchasing Initialization Errors or Warnings after updating Unity Editor

Issue:

• Updating a project to a newer version of the Unity Editor has caused unexpected IAP Package warnings or error messages. 

Cause:

Updating a project to a new version of Unity will force the Package Manager to import the latest version of the In-App Purchasing package into the project. This may be newer and contain differences in Initialization from the version used when the project was last built.

There have been numerous updates to the In-App Purchasing package in the last couple of years, they can be viewed in the In-App Purchasing ChangeLog.

Resolution:

First, check which version of In-App Purchasing your project was updated to. Go to Window > Package Manager > In App Purchasing and check the version number. The steps below differ depending on whether you landed on version 5.0.0 or higher, or are still on a 4.x release.

If you're on In-App Purchasing 5.0.0 or higher: version 5 replaced the old initialization API entirely. UnityPurchasing.Initialize() and ConfigurationBuilder no longer exist, so the steps and code sample below won't apply or compile. Follow the Upgrade from IAP version 4 to version 5 guide instead, which covers the new StoreController-based initialization flow and the rest of what changed.

If you're still on a 4.x release: the warnings are most often caused by Unity Gaming Services not being initialized before IAP. The fix depends on how your project integrates IAP.

If you are using a codeless IAP integration, be sure to check both the Automatic Initialization checkboxes in the Editor > Services > In-App Purchasing > IAP Catalog panel. Doing so will ensure that Unity Gaming Services (a dependency of IAP) is initialized before the IAP system.

If you are using a coded IAP Integration, be sure to Initialize UGS before initializing IAP

await UnityServices.InitializeAsync();
...
UnityPurchasing.Initialize(this, builder);