While there has been no public announcement, makers with agents running on the Claude Sonnet 4.5 orchestration model are now being shown a warning message announcing the impending retirement of the model on May 30, 2026.

If you have a production agent running on this model, you can delay this retirment through June 29, 2026 by clicking the Delay Retirement button. To emphasize, makers must proactively click this button from within the impacted agent to ensure that it is able to run on Sonnet 4.5 for an additional month.

The natural successor to this model is Claude Sonnet 4.6, which Microsoft offers as the default model for all Copilot Studio environments that have Anthropic models enabled. It has proven to be a reliable model with one deficiency: at this time, Copilot Studio's Claude models are not able to generate file outputs with the Code Interpreter functionality.