Checked fact 15627 Sep 2026Agents and apps
The changelog lists 114 entries under 2.1.280.
The exact words it rests on
2.1.280 September 22, 2026
What the source said when we opened it, on 27 Sep 2026.
The source
Claude Code changelog
Checked
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In the story
Claude Code 2.1.280 sets Opus 5.5 as the default Opus model, with a 1M-token window 27 Sep 2026
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