By Hamza Faisal

GitHub is cleaning house again. The company announced on October 15 that it will retire three more AI models across all GitHub Copilot experiences — including Copilot Chat, inline edits, ask and agent modes, and code completions — on November 16, 2026.

The models on the chopping block are Claude Opus 4.8, Claude Opus 5, and GPT-5.6 Terra. GitHub says developers should switch to the suggested replacements before the cutoff: Claude Opus 5.5 for both Opus models, and GPT-6.1 Sol or GPT-6 Luna for the GPT one.

One exception for annual subscribers

There is a single carve-out. Claude Opus 4.8 will remain available to individual GitHub Copilot subscribers on annual plans, so they keep an Opus offering. Everyone else — including organizations on Copilot Business and Copilot Enterprise — loses all three models on November 16.

For Enterprise and Business customers, GitHub says the replacements are automatically enabled under default model policies unless an administrator has turned off the global default or explicitly disabled the new models. No action is required to remove the old models after the deadline — they simply stop working.

The third purge in a month

This is the third deprecation wave this month. Developer-tool analysts note GitHub has already retired 10 Copilot models since October 2, and another six — including GPT-5.5, GPT-5.4 and its mini variants, Gemini 3.7 Flash, and Grok 4.5 — are slated to disappear on October 19.

The pace reflects how fast the underlying models are turning over. Each new generation arrives with better coding benchmarks, and GitHub would rather push developers onto newer models than let the roster keep sprawling.

Test the replacements before the cutoff

For casual users the change will be nearly invisible, since GitHub enables the replacement models automatically. But developers who have pinned a specific model in their editor config, or built team workflows around Opus 5 or GPT-5.6 Terra, should test the replacements against real work now.

Model behavior differs in subtle ways — how it writes code, reasons through multi-file edits, and handles long refactors. The cost of discovering a difference on November 16 is a broken workflow on a Monday morning.

The November 16 cutoff gives teams roughly a month to migrate. GitHub Enterprise customers with questions are encouraged to contact their account team. After that, the three retiring models disappear from the model picker for good — except for that one group of annual-plan subscribers still holding onto Opus 4.8.

By Hamza Faisal