# Codex GPT-5.5 Retirement: What Your Team Should Check > OpenAI retired GPT-5.5 from Codex for ChatGPT sign-ins on 14 October 2026. Here is what changed, who is affected and what to check before work breaks. 17 October 2026 · Plain English · What's new · 6 min read · https://bridge-terminal.com/atlas/blog/codex-gpt-5-5-retirement-what-to-check/ ## The short version - On 14 October 2026 at noon PDT (19:00 UTC), OpenAI retired the GPT-5.5 model from Codex for people signed in with a ChatGPT account. - Codex sessions that use an API key, and the OpenAI API itself, are not affected by this retirement. - Anything that still names gpt-5.5, such as team defaults, saved settings, managed configurations, custom agents, scheduled tasks and scripts, needs to be updated. - OpenAI's changelog points users to GPT-6.1 Sol (gpt-6.1-sol) when it is available to their plan and client. - The lasting lesson: keep a list of every place your team chooses an AI model, because makers retire models on their own schedule. If your team uses OpenAI Codex and signs in with a ChatGPT account, the GPT-5.5 model stopped working there on 14 October 2026. OpenAI's changelog says it retired at noon PDT (19:00 UTC) that day. Anything that still asks for that model by name needs a new choice, and OpenAI points to GPT-6.1 Sol as the replacement when your plan and app offer it. This article explains what changed, who is affected, what to check this week, and why model retirements are a routine part of building with AI coding agents. ## What changed in Codex on 14 October 2026? Codex is OpenAI's AI coding agent. Behind every agent sits a "model", the AI system that reads your request and writes the code. Models have names and version numbers, and their makers eventually switch old ones off. OpenAI's Codex changelog, in an entry dated 2026-10-14, says that GPT-5.5 retires from Codex for users signed in with ChatGPT. The time given is noon PDT (Pacific Daylight Time), which is 19:00 UTC. From then on, a request for that model by name is no longer available to those users. The same entry tells people to use GPT-6.1 Sol, written as `gpt-6.1-sol` in settings, "when available to your plan and client". That wording matters. Your plan or app may not offer the replacement, so check what your own account shows before you change anything. ## Who is affected, and who is not? The answer depends on how people sign in to Codex. - **Signed in with a ChatGPT account:** affected. GPT-5.5 is gone from Codex for these users. - **Using an API key:** not affected. An API key is a secret code that lets software talk to a service directly, billed by use, instead of through a person's ChatGPT login. The changelog says the OpenAI API and Codex sessions authenticated with an API key are not affected. So a developer who logs in with a ChatGPT plan and a colleague who runs Codex with an API key can have different experiences on the same day. If something works on one laptop and fails on another, check the sign-in method first. ## What should we check this week? The changelog lists the places where an old model name may be hiding. It says to check anything that still references `gpt-5.5`: 1. **Team-level default model selections.** If your company sets a default model for everyone, that setting needs a new value. 2. **Saved model settings.** Individuals may have chosen a model in their own settings months ago and forgotten. 3. **Admin-managed configurations.** Settings that an administrator controls centrally. 4. **Custom agents.** Specialised helpers your team set up, each of which may name its own model. 5. **Recurring scheduled tasks.** Jobs that run on a timer, often unwatched, and so the likeliest to fail without anyone noticing. 6. **Scripts.** Small automated programs that call Codex and name the model in their instructions. For a non-engineer, the practical move is to ask one question in your team chat: "Does anything we run name GPT-5.5?" Then ask whoever answers to look at the six places above. Scheduled tasks and scripts deserve the most attention, because nobody is watching when they run. ### Where to get reliable details For model names and plan details, rely on OpenAI's own changelog and help pages rather than third-party summaries. Names of models change quickly and secondhand posts can be out of date. ## What else shipped in Codex this month? The retirement is the item with a date, but two other entries are worth a glance. **Codex CLI 0.163.0, 2026-10-15.** The CLI is the command-line version of Codex, which you use by typing in a terminal window. This release added a searchable settings panel (`/config`), and changes to supported settings can apply immediately. You can send a follow-up message while Codex is responding to steer it, and interrupting a turn also stops active Code Mode cells. Independent read-only tools, such as skill, memory and conversation-history lookups, can run in parallel. Fixes include better handling of permissions when you resume a thread. **GPT-6.1 Sol Ultrafast, 2026-10-08.** A mode that speeds up how quickly GPT-6.1 Sol produces text in Codex and ChatGPT Work. The changelog says it is available on Pro $500 and eligible Enterprise and Edu plans, and that it is off by default for Enterprise, so a workspace owner must enable it. That is a decision for a manager, not something every user gets automatically. ## Why do AI models keep being retired? Models are not like software you buy once. They are services that the maker runs, improves and eventually switches off. The pattern is predictable: a newer model arrives, and the old one is given a date. For a team, this creates a hidden dependency. Your work may rely on a model name that someone typed into a settings file a long time ago. When the date passes, the name stops working for the affected users. Three habits reduce the risk: - **Keep one list.** Write down every place your team chooses a model: defaults, agents, schedules, scripts. A shared page is enough. You cannot update what you cannot find. - **Name an owner.** One person watches the maker's changelog and tells the team when a date is announced. - **Test the replacement on real work.** A newer model is not automatically better for your tasks. Run a small, representative piece of work on the new model and compare the result with what you got before. Do not switch every automated job on the same afternoon. ### Does choosing a different tool avoid this? Not by itself. Other tools also add and change models. Claude Code, for example, lets you pick a model, and its changelog shows new ones arriving: version 2.1.293, dated 7 October 2026, added Claude Haiku 5.5. If you compare tools, ask how much notice you get and how many places you have to edit when a model changes. ## What does this mean for budgets and planning? A new default model can change how fast work finishes and how much of your plan's allowance it uses. The changelog entries we read do not say whether GPT-6.1 Sol will cost you more or less, so do not assume either. Watch your own usage for a week after switching, and ask your admin before turning on extras such as Ultrafast mode, which is limited to certain plans. ## How does Atlas relate to this? This news is about Codex, and Atlas does not run on Codex. [Atlas](https://bridge-terminal.com/atlas/) is a team of AI engineers built on Claude Code. Each engineer is its own Claude Code session with a written role, and its model and effort are tuned to that role. So this particular retirement does not touch Atlas, but the habit of knowing where your team chooses a model applies to any AI tool. ## Conclusion GPT-5.5 left Codex for ChatGPT sign-ins on 14 October 2026. If your team uses Codex that way, search your defaults, saved settings, managed configurations, custom agents, scheduled tasks and scripts for `gpt-5.5`, and move them to the replacement your plan offers, which OpenAI's changelog gives as GPT-6.1 Sol. Then keep a standing list of where models are chosen, so the next retirement date is a quick check instead of a surprise. ## Questions people ask ### When was GPT-5.5 retired from Codex? OpenAI's Codex changelog says GPT-5.5 retired for users signed in with ChatGPT on 14 October 2026 at noon PDT (19:00 UTC). ### Does the GPT-5.5 retirement affect Codex with an API key? No. The changelog says the OpenAI API and Codex sessions authenticated with an API key are not affected. ### What replaces GPT-5.5 in Codex? OpenAI's changelog says to use GPT-6.1 Sol (gpt-6.1-sol) when it is available to your plan and client. Check what your own account offers. ### What do I need to update after the GPT-5.5 retirement? Check anything that still references gpt-5.5: team default model selections, saved model settings, admin-managed configurations, custom agents, recurring scheduled tasks and scripts. ## About Atlas: Know where your team picks its AI model This news concerns Codex, and Atlas does not run on it: Atlas is a team of AI engineers built on Claude Code, with model and effort tuned to each engineer's role. The lesson still carries over: know which model each role uses. — https://bridge-terminal.com/atlas/ ## Sources - [OpenAI Codex changelog (GPT-5.5 retirement, CLI 0.163.0, Ultrafast)](https://learn.chatgpt.com/docs/changelog) - [Claude Code changelog](https://code.claude.com/docs/en/changelog) _Researched and drafted with Claude, then checked against the sources above. Atlas is an independent product, not affiliated with Anthropic or OpenAI._