What changed
On December 14, 2026 GitHub will remove these models across Copilot Chat, inline edits, ask and agent modes, and code completions: Claude Fable 5 (replacement: Claude Fable 5.2), Claude Haiku 4.5 (Claude Haiku 5.5), Gemini 3.8 Flash (Gemini 4 Hydrogen), Gemini 4 Argon (Gemini 4 Carbon), Grok 4.6 (Grok 4.7) and Kimi K3 (replacement to be announced). Claude Haiku 4.5 stays available to individual subscribers on annual plans. Business and Enterprise orgs using default model enablement get the replacements switched on automatically.
Who it affects
All Copilot plans and surfaces, and Business or Enterprise admins who have turned off default model enablement.
What to do
Move workflows, custom agents and integrations off these models before December 14. Admins with default enablement off should turn on the replacement model policies.