GPT-5.5 changelog

Every change to GPT-5.5 that Modelpeers has recorded, newest first, each with the source it came from. The record starts Apr 23, 2026.

All (7)Releases (3)Retiring (2)Breaking changes (1)Quality (1)

October 2026

GPT-5.5, OpenAI Codex and ChatGPT

3 products from OpenAI

Retired2w

GPT-5.5 retired from Codex and ChatGPT

At noon PDT (19:00 UTC) on October 14, 2026, GPT-5.5 retired from Codex for ChatGPT sign-in. Replacements are GPT-6.1 Sol on paid plans and GPT-6 Luna on Free and Go. API-key sessions are not affected.

Who is affected:: Codex and ChatGPT users and scheduled tasks that selected GPT-5.5.
Action needed:: Replace gpt-5.5 with gpt-6.1-sol in defaults, custom agents, scheduled tasks and scripts.

September 2026

GPT-5.5, ChatGPT and OpenAI Codex

3 products from OpenAI

RetiringSep 14, 2026

GPT-5.5 to retire from ChatGPT, ChatGPT Work and Codex on October 14

OpenAI announced GPT-5.5 would retire from ChatGPT, ChatGPT Work and Codex on all plans on October 14, 2026. The API is not affected.

Who is affected:: ChatGPT and Codex users and admins who select GPT-5.5.
Action needed:: Update workspace defaults, saved settings, custom agents and scripts that select gpt-5.5.

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