What changed
Version 2.1.280 added Claude Opus 5.5 (claude-opus-5-5) at $4 input and $20 output per million tokens. The default model on Pro and Team Standard changed from Sonnet to Opus, matching Max, Team Premium and Enterprise. Anthropic’s launch post says five-hour usage limits went up for Pro, Max, Team and seat-based Enterprise plans, and that Opus 5.5 can’t run with thinking turned off.
Who it affects
All Claude Code users. Pro and Team Standard users get a new default model.
What to do
Update to 2.1.280 or later. If you prefer Sonnet, pin it with /model.