OpenAI to retire GPT-5.5 on Oct 14, replace with newer models

OpenAI will retire GPT-5.5 on October 14, 2026, affecting ChatGPT, ChatGPT Work, and Codex. It will be replaced by GPT-5.6 Sol, a mid-tier coding model, and GPT-6 Astra, OpenAI's most advanced model yet. Regular users face seamless transition while developers must manually migrate workflows before the deadline.