GitHub Copilot retires GPT-5.5, GPT-5.4 and four other models
Copilot Chat, agent mode and code completions drop GPT-5.5, GPT-5.4, GPT-5.4 mini, GPT-5 mini, Gemini 3.7 Flash and Grok 4.5 on October 19.
Why it matters. Enterprise admins may need to enable replacements such as GPT-6.1 Sol and GPT-6 Luna in model policies before users see them.
Source: GitHub changelog