Posts claim Fable 5.1 is quietly serving a 'Fable 5.5', and Anthropic has said nothing

Since yesterday, posts on X claim that Fable 5.1 sometimes answers with a newer model. One user said the routing that had stopped for a few days reopened for some accounts and looks like an updated checkpoint, and suggested testing by asking "do you know tibo the reset guy?" without search. Another said they got Fable 5.5 and it nailed a controller in two prompts, and a post predicting a release next Tuesday drew 1,000 likes.

All of this is user observation. Anthropic has never used the name Fable 5.5 in any document and has said nothing about routing or a release date. When it shipped Opus 5.5, the models it named as next were Sonnet 5.5 and Haiku 5.5. Until Anthropic speaks, there is no way to know whether these posts are right.