Last verified: June 13, 2026
Model Accuracy Note — Verified June 13, 2026
Retiring June 15, 2026: the original Claude Opus 4 (claude-opus-4-20250514) and Claude Sonnet 4 (claude-sonnet-4-20250514) — the May 2025 models. These are not Opus 4.6 or Sonnet 4.5, which remain active. Current models: Fable 5 · Opus 4.8 · Sonnet 4.6 · Haiku 4.5. Current model tracker →
claude-sonnet-4-20250514 and claude-opus-4-20250514 — the original Claude 4.0 models from May 2025. API retirement is June 15, 2026. Migrate to Claude Sonnet 4.6 (claude-sonnet-4-6) and Claude Opus 4.8 (claude-opus-4-8).
If you are still running the original Claude Sonnet 4 or Opus 4 model strings in production, you have a hard deadline: June 15, 2026. After that date, calls to claude-sonnet-4-20250514 and claude-opus-4-20250514 return an error — there is no automatic failover to a newer model. Here is exactly what is retiring, what to migrate to, and the breaking changes to plan for.
Claude Model Lifecycle Status (June 2026)
| Model | API ID | Status | Replacement |
|---|---|---|---|
| Claude Opus 4 (original) | claude-opus-4-20250514 | ⚠ Retires June 15, 2026 | claude-opus-4-8 |
| Claude Sonnet 4 (original) | claude-sonnet-4-20250514 | ⚠ Retires June 15, 2026 | claude-sonnet-4-6 |
| Claude Fable 5 | claude-fable-5 | ✓ Current — top tier | — |
| Claude Opus 4.8 | claude-opus-4-8 | ✓ Current Opus flagship | — |
| Claude Sonnet 4.6 | claude-sonnet-4-6 | ✓ Current | — |
| Claude Haiku 4.5 | claude-haiku-4-5 | ✓ Current | — |
Alias trap: the dateless aliases claude-opus-4-0 and claude-sonnet-4-0 resolve to the retiring ...-20250514 snapshots — they go offline too. Claude Opus 4.6, Opus 4.7, Opus 4.5, and Sonnet 4.5 are separate, still-active models and are not affected by this retirement.
What’s Being Deprecated
Anthropic is retiring the original Claude 4.0 model versions — the ones that shipped in May 2025. These are distinct from the 4.x versions released since. The specific API strings going offline:
| Model | API String (retiring) | Retirement Date |
|---|---|---|
| Claude Sonnet 4 (original) | claude-sonnet-4-20250514 |
June 15, 2026 |
| Claude Opus 4 (original) | claude-opus-4-20250514 |
June 15, 2026 |
These are not the latest Claude 4 models. If you have been on Anthropic’s recommended alias endpoints, you are likely already on a current model. This deprecation primarily affects teams that pinned the specific 20250514 version strings in their API calls.
What to Migrate To
Anthropic’s recommended replacement within the same tier:
| Retiring | Migrate To | API String |
|---|---|---|
| claude-sonnet-4-20250514 | Claude Sonnet 4.6 | claude-sonnet-4-6 |
| claude-opus-4-20250514 | Claude Opus 4.8 | claude-opus-4-8 |
These are major upgrades, not just version bumps. Both current models ship a 1 million token context window at standard API pricing (no long-context premium), and the Opus line has advanced two full generations — 4.6, then 4.7, then 4.8 — since the original 4.0. For the most capable tier overall, Anthropic now offers Claude Fable 5 (claude-fable-5), a new tier that sits above Opus.
Breaking Changes When You Migrate
Moving off the original 4.0 strings is usually a model-ID swap, but the current models removed several request parameters. If you are jumping to Opus 4.8 or Fable 5, plan for these — each returns a 400 if left in:
| Removed parameter | Replacement |
|---|---|
thinking: {type:"enabled", budget_tokens:N} |
Adaptive thinking — thinking: {type:"adaptive"} + output_config.effort (low/medium/high/xhigh/max) |
temperature / top_p / top_k |
Removed — steer behavior with prompting instead |
Assistant-turn prefills (request ending on an assistant message) |
Structured outputs — output_config.format |
On Sonnet 4.6 and Opus 4.6 the fixed thinking budget is deprecated but still functional; on Fable 5, Opus 4.7, and Opus 4.8 it is fully removed. A global search for 20250514 in your codebase is the fastest way to find every call that needs changing.
How This Fits the Claude Model Timeline
| Model | Released | Status |
|---|---|---|
| Claude Sonnet 4 / Opus 4 (original) | May 2025 | ⚠ Retire June 15, 2026 |
| Claude Haiku 4.5 | October 2025 | ✅ Current speed/cost tier |
| Claude Opus 4.6 | February 2026 | ✅ Active (superseded by 4.8) |
| Claude Sonnet 4.6 | February 2026 | ✅ Current production default |
| Claude Opus 4.8 | 2026 | ✅ Current Opus flagship |
| Claude Fable 5 | 2026 | ✅ Current top tier (above Opus) |
What If You Don’t Migrate Before June 15?
API calls to claude-sonnet-4-20250514 or claude-opus-4-20250514 after June 15, 2026 will return errors. There is no automatic failover to a newer model — the call simply fails. If you have any production systems, scheduled jobs, or automated pipelines using these version strings, audit them now. A global search for 20250514 in your codebase is the fastest way to find your exposure.
What Comes After Claude 4.x
The “after” is already here. Since the original Claude 4.0 launched in May 2025, the Opus line has shipped 4.5, 4.6, 4.7, and now 4.8, and Anthropic introduced Claude Fable 5 as a new top tier above Opus. As of June 2026 there is no separately branded “Claude 5” generation; the cadence has been steady point releases within the 4.x Opus, Sonnet, and Haiku families, plus the new Fable tier. The practical takeaway: migrating off the retiring 4.0 strings puts you on models that are materially more capable, with a 1M-token context window as the new baseline.
Which Claude models retire on June 15, 2026?
The original Claude Sonnet 4 (claude-sonnet-4-20250514) and Claude Opus 4 (claude-opus-4-20250514), plus their dateless aliases claude-sonnet-4-0 and claude-opus-4-0. Opus 4.6, Opus 4.7, and Sonnet 4.5 are separate, still-active models and are not affected.
What should I migrate to from Claude Sonnet 4 and Opus 4?
Sonnet 4 migrates to claude-sonnet-4-6 (Claude Sonnet 4.6); Opus 4 migrates to claude-opus-4-8 (Claude Opus 4.8). Both ship a 1M token context window at standard pricing. For the most capable tier overall, Anthropic also offers Claude Fable 5 (claude-fable-5).
Is migrating just a one-line model-string change?
Often, but not always. The current models removed temperature, top_p, top_k, the fixed budget_tokens thinking budget, and assistant-turn prefills — each returns a 400 if left in. Replace budget_tokens with adaptive thinking plus output_config.effort, and replace prefills with structured outputs.
What happens if I call the retired model after June 15?
The API returns an error — there is no silent failover to a newer model. Audit for the string 20250514 in your codebase before the deadline.
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