Claude Fable 5.5 release date: what is confirmed and what is rumored

Anthropic has announced three models in the 5.5 family and Fable 5.5 is absent from every one of its pages. The model deprecations table on platform.claude.com, read on October 6, lists claude-fable-5-1 and claude-mythos-5-1 as the newest Fable and Mythos models, and the Anthropic newsroom carries no Fable 5.5 entry. The September 22 Opus 5.5 announcement names the rest of the family: "Claude Sonnet 5.5 and Claude Haiku 5.5 will follow in the coming weeks." Sonnet 5.5 shipped September 28.

Since October 1, X users including @chetaslua and @cherry_mx_reds have reported a newer model answering behind the Fable 5.1 label, and one account predicted a launch the following Tuesday. Chubby (@kimmonismus), who tracks these claims, wrote on October 2: "I can't verify any of this." Emergent reported on October 5 that an X account claims a November arrival around Anthropic's IPO; the AILately.com Desk could open neither the post nor any evidence of which model produced the shared demos, so that claim stays unverified.