Claude Opus 4.8 changelog

Claude Opus 4.8 fast mode is deprecated and ends November 30, 2026

Fast mode for Claude Opus 4.8 is deprecated and will be removed on November 30, 2026. After removal, requests with speed set to fast will return an error.

Takes effect Nov 30, 2026 · in 29 days

Who is affected:

Developers who send fast mode requests to Claude Opus 4.8 will get errors after removal.

Action needed:

Migrate fast mode requests to Claude Opus 5.5 before November 30, 2026.

Copilot to remove Claude Opus 4.8, Claude Opus 5 and GPT-5.6 Terra on November 16

Copilot will deprecate Claude Opus 4.8 and Claude Opus 5 (replace with Claude Opus 5.5) and GPT-5.6 Terra (replace with GPT-6.1 Sol or GPT-6 Luna) on November 16, 2026. Opus 4.8 stays for individual annual-plan subscribers.

Takes effect Nov 16, 2026 · in 15 days

Who is affected:

Copilot users and integrations pinned to those models.

Action needed:

Move to the suggested alternatives before November 16, 2026.

Claude Code Max users default to fast mode on Opus 4.8

In Claude Code, Max plan users now default to fast mode when using Claude Opus 4.8.

Who is affected:

Claude Code users on the Max plan.

What to do:

Run /fast to turn fast mode off if you prefer standard speed.

Claude Opus 4.8 released

Claude Opus 4.8 launched with a 1M token context window by default and 128k max output, priced at $5 / $25 per million tokens like Opus 4.7. Fast mode costs $10 / $50.

Who is affected:

Developers and subscribers using Claude Opus 4.7.

What to do:

Test claude-opus-4-8 and note that effort now defaults to high.