GitHub retires six Copilot models, including GPT-5.5, GPT-5.4 and Grok 4.5
As of October 19, 2026, six models leave most Copilot experiences, with GPT-6.1 Sol, GPT-6 Luna, Gemini 3.8 Flash and Grok 4.7 named as replacements.
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GitHub deprecated six models across most GitHub Copilot experiences on October 19, 2026, according to a changelog post published the same day. The affected surfaces are Copilot Chat, inline edits, ask and agent modes, and code completions. The six models are Gemini 3.7 Flash, GPT-5.5, GPT-5.4, GPT-5.4 mini, GPT-5 mini and Grok 4.5. GitHub first announced the retirement on September 18, 2026, 31 days before the cutoff.
GitHub maps each retired model to a suggested replacement. GPT-5.5 and GPT-5.4 point to GPT-6.1 Sol. GPT-5.4 mini and GPT-5 mini point to GPT-6 Luna. Gemini 3.7 Flash maps to Gemini 3.8 Flash, and Grok 4.5 maps to Grok 4.7. Four OpenAI models collapse into two. The post says no action is required to remove the deprecated models, but tells users to update workflows and integrations to supported models. Enterprise administrators may need to enable the alternatives through model policies in Copilot settings. Enabled models appear in the Copilot Chat model selector in VS Code and on github.com, and admins can check individual Copilot settings to confirm a model’s policy is on. GitHub directs enterprise customers with questions to their account manager.
The admin step gained an API the same day. A separate October 19 changelog post says GET and PATCH REST endpoints for Copilot model policies are now 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) and organization (/orgs/{org}/copilot/model-policies). Per that post, enterprise policies can delegate model control to organizations (organization mode) or to teams and apps (enterprise teams mode). For admins running many organizations, that is a scripted path to enabling GPT-6.1 Sol or GPT-6 Luna instead of editing settings pages one by one. The API post does not list required token scopes or which plans can use the endpoints.
More retirements are scheduled. The deprecation notice links an October 15 post titled “Upcoming deprecation of selected GitHub Copilot models in mid-November” but does not summarize which models it covers. The October 19 notice says nothing about pricing or premium request multipliers for the replacement models, and it does not say when each replacement reached every Copilot client. It also does not define “most”: the post does not name which Copilot experiences, if any, still offer the retired models.
Source: GitHub, October 19, 2026.
Why it matters under load: Any script, extension or agent config that pins GPT-5.5, GPT-5.4 or Grok 4.5 by name now needs a new model ID, and in enterprises where admins have not enabled the replacements through model policies, those models will not appear in the selector.