claude-opus-4-6) and Claude Sonnet 4.6 (claude-sonnet-4-6) are current. Original Claude 4.0 models deprecated — retiring June 15, 2026.Anthropic releases model updates frequently and the naming can be confusing. This page tracks the current Claude model lineup, the exact API strings to use, what’s deprecated, and what’s coming next. Bookmark it and check back — it’s updated when Anthropic ships changes.
Current Models (April 2026)
| Model | API String | Context | Best For |
|---|---|---|---|
| Claude Opus 4.6 | claude-opus-4-6 |
200K (1M beta) | Complex reasoning, long-horizon tasks, maximum capability |
| Claude Sonnet 4.6 | claude-sonnet-4-6 |
200K (1M beta) | Production default — near-Opus performance at lower cost |
| Claude Haiku 4.5 | claude-haiku-4-5-20251001 |
200K | Speed, cost efficiency, high-volume tasks |
Deprecated Models (Action Required)
| Model | API String | Retirement Date | Migrate To |
|---|---|---|---|
| Claude Sonnet 4 (original) | claude-sonnet-4-20250514 |
June 15, 2026 | claude-sonnet-4-6 |
| Claude Opus 4 (original) | claude-opus-4-20250514 |
June 15, 2026 | claude-opus-4-6 |
If you have 20250514 in any API calls or model strings in production code, you have until June 15 to update them. Search your codebase for that date string now.
What Changed From 4.0 to 4.6
The Claude 4.6 models (released February 2026) are meaningful upgrades over the original 4.0 release (May 2025). Key improvements in Sonnet 4.6: near-Opus-level performance on coding and document comprehension, dramatically improved computer use (navigating browsers, filling forms, operating software), better instruction-following with fewer errors, and the 1M token context window in beta. Opus 4.6 adds the same 1M context with additional improvements to long-horizon reasoning and multi-step agentic tasks.
Model Naming: How It Works
Anthropic uses a generation.version format. The “4” is the major generation (fourth architecture generation). The “.6” is a version increment within that generation — a meaningful capability update without a full architecture change. Haiku, Sonnet, and Opus are tiers within each generation: speed/cost, balanced, and maximum capability respectively. The date suffix in API strings (like 20250514) is the training cutoff snapshot used for that specific release.
What’s Coming Next
Claude 5 is expected Q2-Q3 2026 based on Anthropic’s release cadence. No official announcement as of April 2026. Early signals from Vertex AI logs suggested a “Fennec” codename for Claude 5 Sonnet. As always with Anthropic releases, assume the new Sonnet tier will outperform current Opus on most benchmarks at a lower price point. See Claude 5 Release Date: What We Know for the latest.
Model Selection for API Developers
For most production use cases in April 2026: use claude-sonnet-4-6 as your default. It handles the vast majority of tasks at better economics than Opus. Use claude-opus-4-6 for tasks that require maximum reasoning depth — complex multi-step analysis, difficult coding problems, long-horizon agentic runs. Use claude-haiku-4-5-20251001 for high-volume, latency-sensitive, or cost-constrained tasks where raw capability is less critical than speed.
What is the latest Claude model right now?
As of April 2026: Claude Opus 4.6 (claude-opus-4-6) and Claude Sonnet 4.6 (claude-sonnet-4-6), both released February 2026. Claude Haiku 4.5 is the current speed/cost tier.
Is Claude Sonnet 4.6 better than Claude Opus 4?
Yes, in most practical benchmarks. Claude Sonnet 4.6 outperforms the original Opus 4.0 on coding, document comprehension, and instruction-following — at a lower price point. This follows Anthropic’s consistent pattern of new Sonnet tiers exceeding prior Opus tiers.
What Claude model string should I use in my API calls?
Use claude-sonnet-4-6 for most tasks. Use claude-opus-4-6 for maximum capability. Use claude-haiku-4-5-20251001 for speed and volume. Avoid claude-sonnet-4-20250514 and claude-opus-4-20250514 — these retire June 15, 2026.
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