WhichBot › What replaced it › What replaced Claude Sonnet 4?
Last checked Oct 28, 2026 · plain English · no paid picks
What replaced Claude Sonnet 4?
Short answer: Claude Sonnet 5.5. Anthropic retired Claude Sonnet 4 on Jun 15, 2026.
What to do: Use Claude Sonnet 5.5.
The facts
| Old | Claude Sonnet 4 |
|---|---|
| Status | Retired. Retired Jun 15, 2026 |
| Replaced by | Claude Sonnet 5.5 |
| Official source | platform.claude.com |
| Last checked | Oct 28, 2026 |
The replacement at a glance
| Claude Sonnet 5.5 | |
|---|---|
| What it is | Anthropic's mid-size model |
| Made by | Anthropic |
| Price | Developer price: $2 in and $10 out per million tokens |
| Good at | Best for: writing, editing; Reads up to 1,000,000 tokens at once; Reads: text, image, PDFs |
| Where it runs | Claude Free+ |
| Status | Current. Not sooner than Sep 28, 2027 |
| Sources | platform.claude.com · claude.com · models.dev |
Related pages
- Claude Sonnet 5.5 vs GPT-6 Sol
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Questions people ask
What replaced Claude Sonnet 4?
Claude Sonnet 5.5. Anthropic retired Claude Sonnet 4 on Jun 15, 2026.
What should I do if I used Claude Sonnet 4?
Use Claude Sonnet 5.5.
Does Claude Sonnet 4 still work?
Retired. Retired Jun 15, 2026
Facts come from the companies' own pages, linked above, and were last checked Oct 28, 2026. Prices are US and can change. Picks are Hector's: no paid picks, sponsors always labeled, and no sponsorship from AI labs. Our policy.