Rumor: Sonnet 5.5 nearly matches Opus 5.5 as OpenAI plans 20+ Dev Day launches

hibzy7 · reddit · 2026-09-29

A Reddit post claims Anthropic's Opus 5.5 and Sonnet 5.5 are outperforming Sol and Astra, with Sonnet 5.5 — released just a day before OpenAI's Dev Day — nearly matching Opus 5.5 on benchmarks. That makes OpenAI's reported plan of 20+ Dev Day launches all the more interesting timing-wise. All model names and plans are unconfirmed community claims.

Related event: Claude Opus 5.5 and Sonnet 5.5 outpace rivals ahead of OpenAI Dev Day(3 posts)→

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