Starting with API version 2026-01, third-party tax apps will receive Global IDs (GIDs) in tax calculation requests and tax summary webhook payloads for all entity references of the summary section. This aligns with how Partners interact with other Shopify APIs.
This is a companion discussion topic for the original entry at https://shopify.dev/changelog/tax-webhook-summary-and-calculation-requests-now-use-global-ids