Claude API 2026-10-21: Breaking Changes Devs Must Fix Now

Anthropic's Claude API version 2026-10-21 now rejects the temperature, top_p, and top_k parameters with a 400 error, and Python SDK 2.0 breaks MessageParam constructors, according to byteiota. Two additional breaking changes take effect on November 30, 2026.

Anthropic’s new API version rejects temperature, top p, and top k with a 400 error. Python SDK 2.0 breaks MessageParam constructors. Two more changes hit November 30. The post Claude API 2026-10-21: Breaking Changes Devs Must Fix Now appeared first on byteiota .