Claude Fable 5.1 and Claude Mythos 5.1 launched
Tech · Releases · Tue, September 1, 2026
Anthropic launched Claude Fable 5.1 and Claude Mythos 5.1, described as its most advanced models for coding and knowledge work.
Every year
| Date | Event | When |
|---|---|---|
| Tue, Jun 30, 2026 | Claude Sonnet 5 launched | 3 mo ago |
| Wed, Jul 1, 2026 | Model entitlements for Enterprise plans (beta) | 3 mo ago |
| Thu, Jul 9, 2026 | Monthly recap in Settings > Reflect (beta), plus break reminders and quiet hours | 3 mo ago |
| Fri, Jul 24, 2026 | Claude Opus 5 launched | 2 mo ago |
| Thu, Aug 6, 2026 | Skill and plugin security scanning (beta) for Enterprise plans | 2 mo ago |
| Tue, Sep 1, 2026 | Claude Fable 5.1 and Claude Mythos 5.1 launched | 24 days ago |
| Thu, Sep 10, 2026 | Smart reports (beta) on Claude Enterprise analyze team usage and costs | 15 days ago |
| Tue, Sep 15, 2026 | Salesforce in Claude plugin (beta) with 37 pre-built sales skills | 10 days ago |
| Tue, Sep 22, 2026 | Claude Opus 5.5 launched, first model in the Claude 5.5 family | 3 days ago |
Also on Sep 1, 2026
| Date | Event | When |
|---|---|---|
| Tue, Sep 1, 2026 | Bear season opens (MN) | Now |
Source, method and history
- Source
- anthropic
- How we know
- From the Releases API (releases.fru.dev), which reads each vendor's changelog.
- Who
- anthropic
- Recurs
- one-off
- More on fru.dev
- releases.fru.dev
- Feed
- Subscribe to Releases
- Changes
- 2026-09-25: added to 2026-09-01