Klaviyo Revision 2024-06-15 Retirement Before June 15, — when and how should I migrate?
Choose when to upgrade Klaviyo integrations off revision 2024-06-15 before support ends on June 15, 2026.
Blockers
- package/klaviyo-api-2024-06-15 — EOL 2026-06-15
- package/klaviyo-api-2024-10-15 — EOL 2026-10-15
- Accumulated breaking changes since 2024-06-15 include the 2025-01-15 subscription payload requirement, campaign structure changes tied to push support, and cursor pagination changes for some flow message endpoints.
Who this is for
- small-team
- low-ops
Candidates
Upgrade now to latest stable revision 2026-01-15
As of 2026-04-03, Klaviyo's current GA revision is "2026-01-15". Moving straight from "2024-06-15" to "2026-01-15" avoids a second migration before the 2026-06-15 retirement, but you must absorb the accumulated breaking changes since "2024-06-15", especially the "2025-01-15" subscription payload requirement, campaign structure changes tied to push support, and cursor pagination changes for some flow message endpoints.
When to choose
Use this when you want one migration instead of an immediate bridge plus a second cleanup later. It is the best choice if you can run regression tests on subscription flows, campaign APIs, and flow-message pagination now.
Tradeoffs
Best long-term position and aligned with Klaviyo guidance, but highest near-term QA burden because you must account for multiple revisions' accumulated changes.
Cautions
Do not rely on post-retirement fall-forward behavior as a migration strategy. Klaviyo says fall-forward can introduce unwanted breaking changes, and if you opt out of fall-forward, retired revision calls return HTTP 410. Newer docs also expose paid features such as Reviews and Custom Objects; those feature families have separate plan requirements even though upgrading the revision header itself is not presented as a separate API price change in the docs as of 2026-04-03.
Move first to revision 2024-10-15 as a low-risk bridge
Revision "2024-10-15" is a smaller step from "2024-06-15" and, as of 2026-04-03, its changelog shows support until 2026-10-15. That gets you clear of the immediate 2026-06-15 retirement window without jumping across the heavier "2025-01-15" breaking-change set in the same release. The revision adds APIs such as Universal Content, Form Reporting, Segment Reporting, Reviews, Tracking Settings, Metric Properties, and profile identity-resolution updates. This is a pragmatic bridge if your current integration only needs continuity and you cannot safely absorb the later consent and campaign payload changes yet.
When to choose
Use this when the deadline risk is higher than the product value of adopting the newest revision immediately. It fits small-team and low-ops situations where you need to get off a retiring revision fast, then schedule a second planned upgrade after validating later breaking changes.
Tradeoffs
Lowest immediate blast radius, but it intentionally creates another upgrade later because "2024-10-15" is not the latest stable revision.
Cautions
This is only a bridge, not an endpoint. As of 2026-04-03, Klaviyo recommends connecting apps to the latest stable revision every 12-18 months, so stopping at "2024-10-15" should come with a dated follow-up plan. As of 2026-04-03, Klaviyo documents separate Reviews pricing based on monthly orders, so do not treat newly visible Reviews endpoints as included features.
Try with your AI agent
$ npm install -g pocketlantern $ pocketlantern init # Restart Claude Code, Cursor, or your MCP client, then ask: # "Klaviyo Revision 2024-06-15 Retirement Before June 15, — when and how should I migrate?"