Codex retires GPT-5.5, moves to GPT-6.1 Sol
OpenAI removed GPT-5.5 from Codex for ChatGPT sign-ins on the 14th of October 2026. Paid plans move to GPT-6.1 Sol, which costs a third as much per output token on the API.
OpenAI's Codex retires GPT-5.5OpenAI retired its GPT-5.5 model from Codex, its AI coding agent, for users signed in with ChatGPT. The change took effect at noon Pacific time on the 14th of October 2026, the Codex changelog says.
The OpenAI API keeps GPT-5.5, the same entry says. So do Codex sessions signed in with an API key, a paid developer key.
GPT-6.1 Sol replaces GPT-5.5 on Plus, Pro, Business, Enterprise and Edu
Paid plans should move to GPT-6.1 Sol "when available", the Codex models page said on the 15th of October. Free and Go users get GPT-6 Luna in the desktop app.
Enterprise and Edu keep GPT-6.1 Sol off until an administrator turns it on, the page says. "Changing a default doesn't grant model access," the admin guide says.
GPT-5.5 users must update 6 places: defaults, settings, configs, agents, tasks and scripts
The changelog lists 6 places that may still pick GPT-5.5. They are workspace defaults, saved model settings, managed configurations, custom agents, scheduled tasks and scripts.
The admin guide does not say what happens to a setting that still names GPT-5.5.
Below we break down the price gap between GPT-5.5 and GPT-6.1 Sol
OpenAI's API price list charges 5 dollars per million input tokens for GPT-5.5 and 2 dollars for GPT-6.1 Sol. Tokens are the small chunks of text a model reads and writes.
Output costs 30 dollars per million for GPT-5.5 and 10 for GPT-6.1 Sol. So GPT-6.1 Sol charges a third as much for the text it writes, by our arithmetic.
Input costs 2.5 times less, by our arithmetic. The GPT-5.5 prices apply to prompts under 272,000 tokens.
Inside Codex, ChatGPT plans pay in credits. The Codex pricing page lists GPT-6.1 Sol at 50 credits per million input tokens and 250 for output, with no rate for GPT-5.5.
What is confirmed: no API shutdown date for GPT-5.5
OpenAI's API deprecations page lists no shutdown date for GPT-5.5, as of the 15th of October.
The retirement pages name replacements by plan. They name no model that takes over a GPT-5.5 setting by itself.
Key facts
GPT-5.5 left Codex for ChatGPT sign-ins on the 14th of October 2026 at 19:00 UTC.
Paid plans move to GPT-6.1 Sol, Free and Go to GPT-6 Luna.
The OpenAI API keeps GPT-5.5.
GPT-6.1 Sol output costs 10 dollars per million tokens, against 30 for GPT-5.5.