Rumor: Anthropic to drop Opus 5.1, Sonnet 5.1 and mystery Fable 5.1 within days

bindureddy · x · 2026-08-24

A leaker claims Anthropic will release multiple new models in the coming days: Opus 5.1, Sonnet 5.1, and Fable 5.1. Opus and Sonnet will reportedly reverse recent regressions and be strictly better than Opus 4.8 and Sonnet 4.6, while the previously unheard-of Fable 5.1 is predicted to top leaderboards. This is a third-party leak and not officially confirmed.

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