GitHub Copilot Retires GPT-5.1 Codex Family

GPT-5.1 Codex Family Removed from GitHub Copilot

As of April 1, 2026, GitHub has retired three models from the GitHub Copilot model catalog: GPT-5.1-Codex, GPT-5.1-Codex-Max, and GPT-5.1-Codex-Mini. The models have been removed from every Copilot surface — Chat, inline edits, ask mode, agent mode, and code completions — across all supported IDEs and platforms.

The deprecation was pre-announced on March 2, 2026, giving users and enterprise administrators approximately one month to evaluate alternatives and update any model preferences or organization policies that referenced the retiring models.

Recommended Replacements

GitHub's primary recommendation is GPT-5.3-Codex, which the team designates as an LTS (Long-Term Support) model with a committed availability window through at least February 2027. GPT-5.3-Codex is suitable as a general-purpose drop-in replacement for the full range of Copilot tasks previously handled by the GPT-5.1-Codex series.

For workflows where response speed is the priority, GitHub points to GPT-5.4 mini as the successor to GPT-5.1-Codex-Mini. GPT-5.4 mini is optimized for low-latency completions and inline edits where time-to-first-token matters more than raw capability ceiling.

Impact on the Copilot Model Catalog

The retirement streamlines the model picker that Copilot users see in their IDEs and on GitHub.com. The three retired models simply disappear from the selector — no user action is required to remove them. Users who had one of the GPT-5.1-Codex variants set as their preferred model will be automatically migrated to the platform default.

Guidance for Enterprise Administrators

Enterprise administrators who manage organization-level model policies will need to take one explicit action: ensure that GPT-5.3-Codex is enabled in their organization's model policy settings. Unlike individual users, organization policies do not automatically inherit new models — an admin must add GPT-5.3-Codex to the approved list for it to be available to organization members.

Admins should also review any automation, scripts, or third-party integrations that reference the retired model identifiers by name, as those identifiers are no longer valid.