GitHub Copilot drops GPT-5.5, GPT-5.4, Gemini 3.7 Flash and Grok 4.5, and opens a model policy API

GitHub deprecated six models across most GitHub Copilot experiences on 19 October 2026, including Copilot Chat, inline edits, ask and agent modes, and code completions. The removals were announced on 18 September, so this is the date they take effect, not a surprise.

Deprecated model	Suggested alternative
GPT-5.5	GPT-6.1 Sol
GPT-5.4	GPT-6.1 Sol
GPT-5.4 mini	GPT-6 Luna
GPT-5 mini	GPT-6 Luna
Gemini 3.7 Flash	Gemini 3.8 Flash
Grok 4.5	Grok 4.7

GitHub says no action is needed to remove the old models. The catch is the other direction: Copilot Enterprise admins “may need to enable access to alternative models through their model policies”. If a team’s favourite model vanished from the picker today and nothing replaced it, that policy is the first place to look.

This is a different batch from the four models GitHub retired earlier this month, and GitHub has already flagged another deprecation round for mid-November.

The admin lever: model policy REST API, now GA

On the same day GitHub made GET and PATCH endpoints for Copilot model policies generally available at four levels:

• Enterprise: /enterprises/{enterprise}/copilot/model-policies
• Enterprise teams: /enterprises/{enterprise}/teams/{team_slug}/copilot/model-policies
• Enterprise apps: /enterprises/{enterprise}/copilot/apps/model-policies
• Organization: /orgs/{org}/copilot/model-policies

GitHub says enterprise policies can delegate model control to organizations in organization mode, or to teams and apps in enterprise teams mode.

Why it matters

Copilot’s model list now changes every few weeks. Clicking through settings after each deprecation works for one org. For an enterprise with many orgs and teams, a scheduled script that reads the policies and enables the named replacements is the saner way to keep the model picker from going quiet after the next round.