GitHub announced on October 15 that it will deprecate three models across all Copilot experiences — Chat, inline edits, ask and agent modes, and code completions — on November 16, 2026. The models are Claude Opus 4.8, Claude Opus 5 and GPT-5.6 Terra.

GitHub suggests Claude Opus 5.5 as the replacement for both Opus models, and GPT-6.1 Sol or GPT-6 Luna for GPT-5.6 Terra. Under default model enablement, the alternatives are automatically enabled for Copilot Business and Enterprise customers unless an administrator has disabled them.

One exception applies: Claude Opus 4.8 will remain available to individual Copilot subscribers on annual plans so they retain an Opus offering. The three models themselves are not being retired by Anthropic or OpenAI — only the Copilot route to them closes — so teams with pinned model configs should update them before November 16.