Claude Opus 4 Model Launch and Legacy Model Migration

Anthropic has launched Claude Opus 4, and is migrating users from legacy models, recommending improved performance with the new model.

Apr 20, 2026

At a glance

Decide impact, cost movement, and the next step before reading the full diff.

Affected

Anthropic · claude-opus-4

New Launch

Cost impact

Low · 0/5

Estimated from pricing and window changes

Migration pressure

Medium · 3/5

No explicit deadline yet

Next step

Keep monitoring the official rollout

Do this first, then review field-level details

Impact summary

Use explicit levels instead of abstract charts to judge this change.

Cost

Low

Score 0/50%

Quality

Medium

Score 3/560%

Migration

Medium

Score 3/560%

Reliability

Low

Score 0/50%

Compliance

Low

Score 0/50%

The launch of Claude Opus 4 may require users to migrate from legacy models, which could involve code changes or testing efforts.

Changes

Review changed fields first, then decide whether you need full before/after values.

Before

Claude Console
Craft and test powerful prompts directly in your browser.
self.__next_f.push([1,"4c:[\"$\",\"$L61\",null,{\"children\":[\"$\",\"$L62\",null,{\"title\":\"Legacy models\",\"children\":[[\"$\",\"$L34\",null,{\"contentType\":\"paragraph\",\"minLength\":20,\"className\":\"mb-2 last:mb-0\",\"children\":[\"$\",\"p\",null,{\"children\":\"The following models are still available. Consider migrating to current models for improved performance:\"}]}],[\"$\",\"$L34\",null,{\"contentType\":\"table\",\"children\":[\"$\",\"div\",null,{\"className\":\"overflow-x-auto my-6 text-sm\",\"children\":[\"$\",\"table\",null,{\"className\":\"w-full border-collapse\",\"children\":[[\"$\",\"thead\",null,{\"className\":\"\",\"children\":[\"$\",\"tr\",null,{\"className\":\"border-b-0.5 border-border-400 last:border-b-0\",\"children\":[[\"$\",\"th\",null,{\"className\":\"p-2 pt-0 first:pl-0 last:pr-0 text-left font-semibold text-text-100 border-b-0.5 border-border-400\",\"children\":\"Feature\"}],[\"$\",\"th\",null,{\"className\":\"p-2 pt-0 first:pl-0 last:pr-0 text-left font-semibold text-text-100 border-b-0.5 border-border-400\",\"children\":\"Claude Opus 4.6\"}],[\"$\",\"th\",null,{\"className\":\"p-2 pt-0 first:pl-0 last:pr-0 text-left font-semibold text-text-100 border-b-0.5 border-border-400\",\"children\":\"Claude Sonnet 4.5\"}],[\

After

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Sources

Each source focuses on what it confirms, without repeating the whole article.

docs

Anthropic Models Docs

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