Claude Sonnet 5 becomes Claude Code's default model (2.1.197)

What changed

Claude Code 2.1.197, published June 30, 2026, adds Claude Sonnet 5 and makes it the default, with a native 1M-token context window. Anthropic launched it at a promotional $2 input / $10 output per million tokens, originally due to run through August 31. You need 2.1.197 or later to use it.

Who it affects

All Claude Code users, especially API-key users who pay per token.

What to do

Update to 2.1.197 or later, and if you pin a model, decide deliberately whether to move to Sonnet 5.

Source: https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md