Stop pinning your builds to 2025-10 if you rely on bulk metafield operations. The 2026-10 API version is rolling out, and it contains a silent breaking change in the metafieldsSet mutation that will cause 500 errors in your production pipelines once the deprecation window closes.

I have spent the last two weeks auditing client integrations against the new sandbox environment. The issue isn't just a parameter rename; it’s a shift in how Shopify resolves ownership context for batch writes. If your app or migration script uses the legacy owner_type field, you are one commit away from a data integrity incident.

The Problem: owner_type is Dead

In previous API versions (up to and including 2025-10 ), the metafieldsSet mutation accepted an owner_type argument to specify the resource kind (e.g., PRODUCT , CUSTOMER , COLLECTION ). This allowed developers to batch insert metafields without strictly adhering to the global ID format in every single line of a large payload.

In 2026-10 , owner_type is deprecated.…