Claude Release History: Claude 1 to Fable 5.1 (Sept 2026)

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Current lineup verified 23 September 2026 against the models overview. Dated rows already on this desk were not re-read from the newsroom on this date.

Direct Answer (23 September 2026): Public Claude runs from Claude 1 (March 2023) through the current lineup Fable 5.1, Opus 5.5, Sonnet 5, and Haiku 4.5. Opus 5.5 is the current Opus ($4 / $20, claude-opus-5-5). A ship date for Opus 5.5 was not on the models overview read this day. Opus 5 (24 July 2026, $5 / $25) is legacy. Mythos 5.1 is not in the current public comparison table. Living current-model box: current Claude model version.

2026 changelog (dated)

Date Release Note
Not published on the 23 Sept 2026 models overview Opus 5.5 Current Opus. Daily driver. $4 / $20. API ID claude-opus-5-5. Retirement not sooner than 22 September 2027.
1 Sept 2026 Fable 5.1 / Mythos 5.1 Previously logged on this desk from the newsroom. Mythos 5.1 is not in the current public comparison table.
24 July 2026 Opus 5 Now legacy. Still listed at $5 / $25.
1 July 2026 Fable 5 / Mythos 5 restored After mid-June access suspension.
30 June 2026 Sonnet 5 Current Sonnet. $2 / $10. Available on Free on the 23 September 2026 pricing table.
9 June 2026 Fable 5 / Mythos 5 First public tier above Opus. Mid-June pause, then restore.
28 May 2026 Opus 4.8 Opus upgrade; effort control on claude.ai.
17 Feb 2026 Sonnet 4.6 Then production Sonnet; now superseded by Sonnet 5 as default.
Oct 2025 Haiku 4.5 Still the speed tier.

Earlier generations (status)

Claude 1 → 2 → 3 / 3.5 / 3.7 → Claude 4 / 4.0 date-stamped IDs: historical. Original Sonnet 4 and Opus 4 (20250514) were the June 15, 2026 retirement class. Do not use them in new work.

The pattern that still holds: a new Sonnet often matches or beats the prior Opus at lower cost. Sonnet 5 vs Opus 4.8 is that move again.

FAQ

When was the latest Claude model released?

Fable 5.1 was logged here as 1 September 2026. Opus 5 on 24 July 2026. Sonnet 5 on 30 June 2026. Opus 5.5 is current, and its ship date was not on the models overview read 23 September 2026.

How many Claude versions are there?

More than a dozen public versions across five-plus generations. Four are current on the 23 September 2026 models overview: Fable 5.1, Opus 5.5, Sonnet 5, Haiku 4.5.

Related: current models · pricing.

>Part of the complete guide: Claude Pricing, Plans & Limits

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