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Action requiredKlaviyo · API & integrations · Thu, Oct 15, 2026
Klaviyo API revision 2026-10-15 brings breaking Campaigns API changes
What changed
The omnichannel Campaigns API is now GA and replaces the old request and response shapes. A campaign is a container with audiences, each audience has messages, each message sends on one channel, and the v3 API does not support A/B tests. Universal content display_options also changed shape. The Brands, Text Messaging, Translations and Billing Usage APIs are GA as well.
What to do
If an app or script creates Klaviyo campaigns through the API, have its owner test against 2026-10-15 before upgrading the revision header.
Source
← New SMS and WhatsApp consent block for Shopify checkoutKlaviyo API revision 2024-10-15 reached end of support on Oct 15 →
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