GitHub Copilot to Retire Six Models on Dec 14, With No Successor Yet for Kimi K3

What happened

The deprecation covers all Copilot experiences: Copilot Chat, inline edits, ask and agent modes, and code completions. GitHub’s changelog lists the six models with a suggested alternative for each: Fable 5 by Fable 5.2, Haiku 4.5 by Haiku 5.5, Gemini 3.8 Flash by Gemini 4 Hydrogen, Gemini 4 Argon by Gemini 4 Carbon, and Grok 4.6 by Grok 4.7; the alternative for Kimi K3 reads “to be announced.”

There is one exception: individual Copilot subscribers on annual plans will keep access to Claude Haiku 4.5. Under default model enablement, the suggested alternatives are automatically enabled for Copilot Enterprise and Copilot Business customers unless an administrator has turned off the global default or explicitly disabled the model; no action is required to remove the models after they have been deprecated.

This is the fourth deprecation wave in ten weeks: four models on Oct 2, six on Oct 19, and three more — Claude Opus 4.8, Claude Opus 5 and GPT-5.6 Terra — due on Nov 16, for 19 models retired or scheduled across the four waves.

What it means for users

For users, swapping models is not a simple rename: different models differ in answer quality, speed and price. GitHub says nothing about price in the changelog; on GitHub’s own rate card, some replacements cost more than the models they replace — Gemini 4 Carbon, for example, is set to nearly double in price on Dec 1.

Two models previously recommended as replacements are themselves on this wave’s list: Gemini 3.8 Flash and Kimi K3 were named as alternatives in October’s waves and retire on Dec 14 as well; Grok 4.6 was the successor to Grok 4.5, retired on Oct 19.

Key facts

1. Retirement: On Dec 14, 2026, six models leave all Copilot experiences, including Chat, inline edits, ask and agent modes, and code completions
2. List: Claude Fable 5, Claude Haiku 4.5, Gemini 3.8 Flash, Gemini 4 Argon, Grok 4.6 and Kimi K3
3. Replacements: Fable 5 to Fable 5.2; Haiku 4.5 to Haiku 5.5; Gemini 3.8 Flash to Gemini 4 Hydrogen; Gemini 4 Argon to Gemini 4 Carbon; Grok 4.6 to Grok 4.7; Kimi K3 to be announced
4. Exception: Individual subscribers on annual plans keep access to Claude Haiku 4.5
5. Auto-enable: Under default settings, replacements are automatically enabled for Enterprise and Business customers; no manual removal is needed after deprecation
6. Waves: The fourth wave in ten weeks; 19 models retired or scheduled across the four waves