Claude Sonnet 5.5 launch
Anthropic launched Claude Sonnet 5.5, the second model in the Claude 5.5 family. Sonnet 5.5 is a faster, lower-cost complement to Claude Opus 5.5.
Source: Claude Help Center release notes. Published September 28, 2026.
Daily tracker of new ChatGPT, Claude and Gemini features
Anthropic launched Claude Sonnet 5.5, the second model in the Claude 5.5 family. Sonnet 5.5 is a faster, lower-cost complement to Claude Opus 5.5.
Source: Claude Help Center release notes. Published September 28, 2026.