OpenAI and GitHub set October deadlines for model retirements

Two major coding surfaces published model retirement deadlines on September 16. OpenAI will remove GPT-5.5 from ChatGPT, ChatGPT Work, and Codex on October 14, 2026. GitHub will deprecate selected models across Copilot on October 2, 2026.

The dates are close enough to matter for teams with saved model choices, managed defaults, scheduled jobs, or automation that assumes a particular model remains selectable. The announcements affect different products, so the migration steps are separate.

OpenAI keeps GPT-5.5 in the API

OpenAI’s Codex changelog says GPT-5.5 will retire from ChatGPT, ChatGPT Work, and Codex on all plans, including consumer, Business, Enterprise, and Edu. The retirement does not apply to the OpenAI API.

For Codex sessions authenticated with a ChatGPT sign-in, OpenAI directs users to move from gpt-5.5 to gpt-5.6-sol before October 14. The changelog also calls out workspace defaults, saved model settings, managed configurations, custom agents, scheduled tasks, and scripts as places to check.

That split matters. An API integration using GPT-5.5 is not covered by this notice, while a Codex workflow using ChatGPT authentication is. Teams should inventory both paths instead of treating “GPT-5.5 retirement” as a single platform-wide shutdown.

GitHub’s Copilot deadline arrives first

GitHub says selected Copilot models will be deprecated across Copilot Chat, inline edits, ask mode, agent mode, and code completions on October 2. Its notice asks users to move workflows and integrations to supported alternatives before that date.

Copilot Business and Enterprise administrators may need to enable replacement models through model policies. GitHub recommends checking organization or enterprise Copilot model settings and confirming that the relevant policy is enabled. After deprecation, GitHub says no manual removal action is required.

The GitHub notice does not make the OpenAI retirement universal, and the OpenAI notice does not describe GitHub’s Copilot model set. They are independent vendor announcements with different scopes and deadlines.

A short migration checklist

Start with the October 2 GitHub deadline, then the October 14 OpenAI deadline:

• Export or record model selections in Copilot policies, repositories, agent configurations, scheduled tasks, and scripts.
• Check whether a model identifier is pinned directly or inherited from a workspace or organization default.
• Test the replacement model with representative prompts, tool calls, code review rules, and output limits.
• Keep the OpenAI API path separate from ChatGPT-authenticated Codex sessions in your inventory.
• Update runbooks with the exact product scope and date; do not assume an API deprecation from a ChatGPT or Copilot notice.

For teams managing agent fleets, the practical risk is configuration drift: a workflow can continue to start while silently switching models or losing access to a pinned choice. The two official changelogs give administrators enough notice to find those dependencies before the October deadlines.

Sources

• OpenAI ChatGPT & Codex changelog
• GitHub Changelog: Upcoming deprecation of selected GitHub Copilot models