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Claude 2.1

Anthropic · Claude Opus line · flagship

Released November 21, 2023Replaced by Claude 3 Opus

Claude 2.1 was released by Anthropic on November 21, 2023, as a flagship model in the Claude Opus line.

  • Release 2 of 11 in the Claude Opus line.
  • Came 133 days after Claude 2, released Jul 11, 2023.
  • Replaced by Claude 3 Opus on March 4, 2024, 104 days later.
  • These days the line ships a new model about every 60 days.

No detailed card for this model: we only add numbers published by the maker or by independent benchmarks. Sources: Anthropic · TechCrunch

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Where the Claude Opus line stands

Claude Opus 5.5 is the current model in this line. The card shows how long it has been since the last release against the line's usual gap and its recent ones — the rhythm, not a date.

Claude Opus 5.5

Anthropic · Claude Opus line · flagship
Just releasedreleased 14 days ago — usual gap is ~60

Anthropic's new Opus scores 7 points higher than Opus 5 on the all-round index and costs 20% less per token.

Released Sep 22, 2026 · what changed →
Days since last release
Claude Opus 5.5 · Sep 22, 2026
14
days
Usual gap
60
days
Recent gaps
Claude Opus 5.5 · Sep 2026
60
Claude Opus 5 · Jul 2026
57
Claude Opus 4.8 · May 2026
42
Claude Opus 4.7 · Apr 2026
70

Every Claude Opus release

Newest first. See the full line with every card →

  1. Sep 22, 2026Claude Opus 5.5
  2. Jul 24, 2026Claude Opus 5
  3. May 28, 2026Claude Opus 4.8
  4. Apr 16, 2026Claude Opus 4.7
  5. Feb 5, 2026Claude Opus 4.6
  6. Nov 24, 2025Claude Opus 4.5
  7. Aug 5, 2025Claude Opus 4.1
  8. May 22, 2025Claude Opus 4
  9. Mar 4, 2024Claude 3 Opus
  10. Nov 21, 2023Claude 2.1 · this page
  11. Jul 11, 2023Claude 2