GitHub to deprecate six Copilot models on December 14, 2026

GitHub announced on November 13, 2026 that it will retire six AI models from every GitHub Copilot experience on December 14, 2026, including Claude Fable 5, Claude Haiku 4.5, Gemini 3.8 Flash, Gemini 4 Argon, Grok 4.6 and Kimi K3, and is pointing customers to newer replacements. Details are in the Upcoming deprecation of selected GitHub Copilot models in December changelog entry.

What is changing

• Claude Fable 5 is deprecated in favor of Claude Fable 5.2.
• Claude Haiku 4.5 is deprecated in favor of Claude Haiku 5.5, though it stays available to individual Copilot subscribers on annual plans.
• Gemini 3.8 Flash is deprecated in favor of Gemini 4 Hydrogen.
• Gemini 4 Argon is deprecated in favor of Gemini 4 Carbon.
• Grok 4.6 is deprecated in favor of Grok 4.7.
• Kimi K3 is deprecated, with its replacement to be announced later.

What it means for people who build with AI

The change touches Copilot Chat, inline edits, ask and agent modes, and code completions, and affects both Copilot Enterprise and Copilot Business tiers. Teams that pinned one of these six models or built workflows around them need to update their configuration before December 14, 2026, or risk disruption once the model disappears from the picker.

Availability after December 14, 2026

Replacement models are auto-enabled for Enterprise and Business customers unless administrators have turned off global model defaults, so most teams will shift to the newer models automatically.

Sources

• Upcoming deprecation of selected GitHub Copilot models in December (GitHub, November 13, 2026, official)

Written with AI assistance, strictly from the sources listed above. Before it went live, automated checks verified its dates, sources and every language edition.