GPT-5.5 retires from ChatGPT, ChatGPT Work, and Codex on 14 October 2026

OpenAI has confirmed 14 October 2026 as the hard retirement date for GPT-5.5 across ChatGPT, ChatGPT Work, and Codex on all subscription plans, including consumer, Business, Enterprise, and Edu. After that date, both GPT-5.5 and GPT-5.5 Thinking will stop responding inside those products. The OpenAI API is entirely unaffected.

If you use ChatGPT casually and let OpenAI pick your model for you, you will probably not notice the change. If you have built anything on top of GPT-5.5 through Codex using a ChatGPT sign-in, you need to act before the deadline.

What exactly is being retired, and where

GPT-5.5 launched on 23 April 2026 as OpenAI’s first fully retrained base model since GPT-4.5. It was positioned as the company’s most capable model at the time, with particular strengths in writing, coding, online research, and data analysis. Less than six months later, it is being phased out of the subscription surfaces in favour of newer models.

The retirement covers:

• ChatGPT (all plans)
• ChatGPT Work (all plans)
• Codex when signed in with a ChatGPT account

It does not cover:

• The OpenAI API, GPT-5.5 does not appear on OpenAI’s API deprecations page with any shutdown date
• Codex authenticated with your own API key

That distinction is worth emphasising. If your production integration talks to the API directly, nothing changes on 14 October 2026. If your team’s Codex setup relies on ChatGPT sign-in, you need to migrate.

What you need to switch to

OpenAI recommends two replacement models, each suited to different kinds of work.

GPT-5.6 Sol (gpt-5.6-sol) is the default recommendation for most routine work: normal chat, summarisation, rewriting, structured extraction, and straightforward code generation. Think of it as the sensible starting point for anything that does not demand heavy reasoning.

GPT-6 Astra (gpt-6-astra), which shipped on 3 September 2026 with a 1.05 million token context window and 128K max output, is the recommendation when execution is the bottleneck. Difficult debugging, repository-wide refactoring, terminal automation, browser and desktop agents, and any workflow that requires the model to maintain state across many dependent actions are the cases where Astra earns its place.

Swapping the model name is not quite the whole job. OpenAI’s own documentation notes that higher reasoning effort can improve results on complex tasks but uses more tokens and takes longer. When you migrate, validate that the replacement model’s behaviour and resource consumption match your expectations, not just that the configuration now points to a new name.

The checklist for Codex users on ChatGPT sign-in

Before 14 October 2026, go through each of the following and replace gpt-5.5 with gpt-5.6-sol (or gpt-6-astra where appropriate):

• Workspace defaults in ChatGPT and ChatGPT Work
• Saved model settings
• Managed configurations
• Custom agents
• Scheduled tasks
• Any scripts or automation that select the model by name

In the ChatGPT desktop app, the model and reasoning controls sit beneath the composer. Use those to switch to an available model and adjust reasoning effort from there.

A note on the broader model changes around this date

GPT-5.5 is not the only recent retirement. GPT-5.3-Codex-Spark was deprecated on 14 September 2026 and is no longer available in the ChatGPT desktop app, Codex CLI, or IDE extension. If you are still selecting gpt-5.3-codex-spark anywhere, that work is already overdue.

GPT-5.4 and GPT-5.4 mini remain available on the OpenAI API and in Codex sessions authenticated with an API key, so those are unaffected for now.

One other change worth knowing: the codex mcp-server command was deprecated and the standalone codex-mcp-server binary was removed on 5 September 2026. The Codex app server replaces it. Support for the Chat Completions API in Codex is also deprecated and will be removed in a future release.

For workspace admins

The practical action here is a short audit before the deadline. Pull up your organisation’s workspace defaults for ChatGPT, ChatGPT Work, and Codex. Identify anywhere GPT-5.5 is set as the preferred or default model. Decide whether GPT-5.6 Sol or GPT-6 Astra is the right replacement for each context, and update accordingly.

For most teams, GPT-5.6 Sol will cover the majority of use cases, with Astra reserved for the agent-heavy or complex reasoning workflows. If your organisation has custom agents built in Codex, those need individual attention because a broken agent configuration is more disruptive than a chat conversation that silently falls back to a default.

OpenAI is not offering a legacy option here. When developers asked the company to keep GPT-5.5 available in Codex after retirement, the answer was no. The 14 October 2026 date is firm.