Hey @VKH ,
This isn’t necessarily a limitation of the API version, but a limitation on the store plan. In order to access PII through a custom app, the store will need to be on the Shopify plan or higher.
If you’re looking to do some testing, I would recommend setting up a development store for that: https://help.shopify.com/en/partners/dashboard/managing-stores/development-stores
Development stores have all of the features of the advanced plan, so you won’t experience this limitation.
Hope that helps,
- Kyle G.