Anthropic deprecations (models, parameters, headers, endpoints)
Status: DOCUMENTED; retirement of 8 model ids LIVE_VERIFIED (GET /v1/models/{id} → 404 not_found_error on 2026-09-18); retirement commitments for active models are documentation only.
Sources: https://platform.claude.com/docs/en/about-claude/model-deprecations · release-notes/overview · build-with-claude/fast-mode · agents-and-tools/mcp-connector · api/beta-headers · api/ip-addresses · about-claude/models/migration-guide (retrieved 2026-09-18).
Last verified: 2026-09-18 · Machine-readable: generated/fragments/deprecations/anthropic-deprecations.json.
1. Lifecycle vocabulary and policy
Active → Legacy (no updates) → Deprecated (replacement + retirement date, ≥ 60 days notice by email and docs) → Retired (requests fail). Dates apply to Anthropic-operated platforms (Claude API, Claude Platform on AWS, Microsoft Foundry); Bedrock and Google Cloud keep their own schedules (several models retired on the API remain "deprecated" there). Anthropic commits to preserving weights and may re-release past models; researchers can request retired models through the External Researcher Access Program. Audit usage: Console → Usage → Export (CSV by key and model).
2. Model status table (2026-09-18)
| Model id | State | Deprecated | Retirement | Replacement | Our probe |
|---|---|---|---|---|---|
| claude-fable-5-1 | Active | — | not sooner than 2027-09-01 | 200 | |
| claude-mythos-5-1 | Active (invite only) | — | not sooner than 2027-09-01 | 404 (not exposed to our key) | |
| claude-fable-5 | Active (legacy) | — | not sooner than 2027-06-09 | 200 | |
| claude-mythos-5 | Active (invite only) | — | not sooner than 2027-06-09 | 404 | |
| claude-mythos-preview | Deprecated | 2026-06-09 | to be announced | claude-mythos-5 | 404 |
| claude-opus-5 | Active | — | not sooner than 2027-07-24 | 200 | |
| claude-opus-4-8 | Active (legacy) | — | not sooner than 2027-05-28 | 200 | |
| claude-opus-4-7 | Active (legacy) | — | not sooner than 2027-04-16 | 200 | |
| claude-opus-4-6 | Active (legacy) | — | not sooner than 2027-02-05 | 200 | |
| claude-opus-4-5-20251101 | Active (legacy) | — | not sooner than 2026-11-24 | 200 | |
| claude-opus-4-1-20250805 | Retired | 2026-06-05 | 2026-08-05 | claude-opus-4-8 | 404 |
| claude-opus-4-20250514 | Retired | 2026-04-14 | 2026-06-15 | claude-opus-4-8 | not probed |
| claude-sonnet-5 | Active | — | not sooner than 2027-06-30 | 200 | |
| claude-sonnet-4-6 | Active (legacy) | — | not sooner than 2027-02-17 | 200 | |
| claude-sonnet-4-5-20250929 | Active (legacy) | — | not sooner than 2026-09-29 | 200 | |
| claude-sonnet-4-20250514 | Retired | 2026-04-14 | 2026-06-15 | claude-sonnet-4-6 | 404 |
| claude-3-7-sonnet-20250219 | Retired | 2025-10-28 | 2026-02-19 | claude-sonnet-4-6 | 404 |
| claude-haiku-4-5-20251001 | Active | — | not sooner than 2026-10-15 | 200 | |
| claude-3-5-haiku-20241022 | Retired (still on Bedrock/Vertex) | 2025-12-19 | 2026-02-19 | claude-haiku-4-5-20251001 | 404 |
| claude-3-haiku-20240307 | Retired | 2026-02-19 | 2026-04-20 | claude-haiku-4-5-20251001 | 404 |
| claude-3-5-sonnet-20241022 / -20240620 | Retired | 2025-08-13 | 2025-10-28 | claude-sonnet-4-6 | 404 / — |
| claude-3-opus-20240229 | Retired | 2025-06-30 | 2026-01-05 | claude-opus-4-8 | 404 |
| claude-3-sonnet-20240229, claude-2.1, claude-2.0 | Retired | 2025-01-21 | 2025-07-21 | sonnet-4-6 / opus-4-8 | — |
| claude-1.x, claude-instant-1.x | Retired | 2024-09-04 | 2024-11-06 | claude-haiku-4-5-20251001 | — |
Note: the deprecations page's replacement column was updated over time (e.g. Opus 3 → "claude-opus-4-8" now, "Opus 4.5" in the Jan 2026 release note). The 404 body is {"type":"error","error":{"type":"not_found_error","message":"model: <id>"},"request_id":"…"} — identical for retired ids and for ids our key cannot see, so a 404 alone does not prove retirement.
Upcoming (soonest commitments): Sonnet 4.5 (2026-09-29), Haiku 4.5 (2026-10-15), Opus 4.5 (2026-11-24) — all "not sooner than", no announcement yet.
3. Parameter and behaviour deprecations
| Item | Since | Behaviour | Replacement |
|---|---|---|---|
temperature, top_p, top_k |
Opus 4.7 (2026-04-16) | 400 when non-default on Claude 4.7+ and Mythos Preview; incompatible with thinking on older models; removed from Python SDK v1.0 | omit; prompt / effort |
Manual extended thinking thinking.type: "enabled" + budget_tokens |
4.6 (deprecated) → 5.x (400) | Fable/Mythos 5.x: adaptive only, cannot be disabled | thinking.type: "adaptive" + effort |
| Assistant prefill | Opus 4.6 (2026-02-05) | unsupported on 4.6+ / with thinking on; incompatible with JSON outputs | structured outputs |
tool_choice any / tool |
2026-09-01 | 400 on Fable 5.1 / Mythos 5.1 only | strict tool use |
Disabling thinking at xhigh/max effort |
Opus 5 (2026-07-24) | 400 | disable only at high or below |
output_format |
2026-01-29 | accepted during transition | output_config.format |
cache_control inside tool_result.content / document.source.content |
2025-05-01 | auto-moved if on last block; else validation error | put on parent block |
top_p default |
2025-05-22 | changed 0.999 → 0.99 (set 0.999 to revert) | — |
Text Completions API POST /v1/complete |
legacy | still documented as legacy; removed from Python SDK v1.0 (2026-08-20) | Messages API |
API version 2023-01-01 |
— | deprecated | 2023-06-01 |
4. Beta header deprecations / graduations
Retired: context-1m-2025-08-07 for Sonnet 4.5/4 (no effect since 2026-04-30), computer-use-2024-10-22 (model retired), max-tokens-3-5-sonnet-2024-07-15. Deprecated: mcp-client-2025-04-04 → mcp-client-2025-11-20; managed-agents-2026-04-01 on memory-store endpoints → agent-memory-2026-07-22 (both → 400). Graduated (header optional): files-api-2025-04-14 (GA 2026-08-19; header returns the old shape), skills-2025-10-02 (2026-08-19), ce-user-management-2026-07-13 (2026-08-19), structured-outputs-2025-11-13 (2026-01-29), effort-2025-11-24 and fine-grained-tool-streaming-2025-05-14 (2026-02-05), web search/fetch, tool search, memory, PTC, tool examples headers (2026-02-17), extended-cache-ttl-2025-04-11 (2025-08-13), search-results-2025-06-09 (2025-08-08), thinking-token-count-2026-05-13 (2026-05-27), the 2024 headers for Batches/caching/PDF/token counting (2024-12-17).
5. Feature / endpoint retirements
| Item | Announced | Retired | Replacement |
|---|---|---|---|
| Fast mode on Opus 4.6 | 2026-05-28 | 2026-06-29 (runs standard, no error) | Opus 4.8 / Opus 5 |
| Fast mode on Opus 4.7 | 2026-06-25 | 2026-07-24 (error) | Opus 4.8 / Opus 5 |
/v1/experimental/{generate,improve,templatize}_prompt |
2026-07-17 | 2026-08-17 | — |
| Legacy Workbench | 2026-07-17 | 2026-08-17 | playground |
/v1/organizations/tunnels (Admin API) |
2026-06-22 | migration window | /v1/tunnels + mcp-tunnels-2026-06-22 |
| Priority Tier commitments | — | no longer sold | contact sales |
| Dedicated 1M rate limits | — | 2026-03-13 | standard limits |
| Usage tiers 1–4 | — | 2026-06-26 | Start / Build / Scale |
| TPM limit | — | 2024-11-20 | ITPM + OTPM |
| Build / Scale plans | — | 2024-10-08 | standard suite |
| Egress IPs 34.162.46.92/32, .102.82, .136.91, .142.92, .183.95 | — | phased out | 160.79.104.0/21 |
| console.anthropic.com / docs.anthropic.com | 2025-09-16 | redirects (2026-01-12 / 2025-11-19) | platform.claude.com |
6. Tool version supersessions
computer_toolset_20260801 (GA 2026-08-19) supersedes beta computer_20251124 / computer_20250124 (still available for older models/clouds); computer_20241022, bash_20241022, text_editor_20241022 retired with Sonnet 3.5; text_editor_20250124 (3.7) and text_editor_20250429 (4.x) → text_editor_20250728; code_execution_20250522 (Python only) → code_execution_20250825 / 20260120 / 20260521.