---
title: Changes to metafield definition error codes - Shopify developer changelog
description: Shopify’s developer changelog documents all changes to Shopify’s platform. Find the latest news and learn about new platform opportunities.
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  html: https://shopify.dev/changelog/changes-to-metafield-definition-error-codes
  md: https://shopify.dev/changelog/changes-to-metafield-definition-error-codes.md
---

[Back to Developer changelog](https://shopify.dev/changelog)

March 21, 2022

Tags:

* API
* 2022-04

# Changes to metafield definition error codes

As of GraphQL Admin API version 2022-04, an error returns when a metafield definition is created with invalid characters in either the `key` or the `namespace` fields. The `key` and `namespace` fields can contain only alphanumeric characters, hyphens, and underscores.

[Learn more about the `MetafieldDefinition` object](https://shopify.dev/api/admin-graphql/current/objects/MetafieldDefinition).