An October 15 notice names October 29
Anthropic schedules Haiku 4.5’s removal from the chat, Cowork, and Design selectors on Free, Pro, and Max, including desktop and mobile. Haiku 5.5 replaces it. The notice says the change was announced October 15 and takes effect October 29; it gives no hour or timezone. [1]
The scope matters
Existing conversations remain. The selected model and continued Haiku 4.5 chats switch to 5.5 under this notice. Claude Code, Team, Enterprise, and the Platform API are excluded. A model can be changed before a later response. We have not verified an account’s transition. [1]
Our take
A familiar chat history is useful context, but it is not a promise of identical answers. Before relying on a recurring task, check the model name and compare a small fictional example with your usual standard. Look for changed facts, formatting, and instructions rather than assuming the replacement behaves the same.
Start with the product you actually use and its current model label.