GitHub Copilot Model Deprecations: What's Changing on November 16

GitHub will deprecate three GitHub Copilot models — Claude Opus 4.8, Claude Opus 5, and GPT-5.6 Terra — across every Copilot surface on November 16, 2026, according to a changelog entry GitHub published on October 15. Copilot Chat, inline edits, ask mode, agent mode, and code completion will all stop offering the three retiring models that day. GitHub's suggested replacement is Claude Opus 5.5 for both outgoing Claude models, and either GPT-6.1 Sol or GPT-6 Luna for GPT-5.6 Terra.

A quick refresher on GitHub Copilot

GitHub Copilot is GitHub's AI pair-programming product, built on top of large language models from partners including Anthropic and OpenAI. It shows up across several distinct surfaces — a chat panel, inline code suggestions as you type, a CLI companion, and an increasingly capable agent mode that can carry out multi-step coding tasks on its own. All of those surfaces draw from a shared, centrally managed list of supported models, which is exactly why a single deprecation notice like this one can touch chat conversations, inline edits, and autonomous agent runs all at once.

Which Copilot models GitHub is deprecating on November 16

In an October 15, 2026 changelog post titled "Upcoming deprecation of selected GitHub Copilot models in mid-November," GitHub confirmed it is retiring three models from GitHub Copilot: Claude Opus 4.8, Claude Opus 5, and GPT-5.6 Terra. The removal applies across all Copilot experiences where those models are currently selectable, and it takes effect on November 16, 2026 — a little over three weeks after the notice went live.

This is a distinct notice from GitHub's earlier September 16, 2026 deprecation post, which retired a different set of models. GitHub has been running these model-retirement notices on a recurring cadence throughout 2026 as it rotates in newer model versions from Anthropic and OpenAI and rotates out older ones. The November 16 wave is the one developers need to plan around right now, since it is the next deadline on the calendar.

What replaces each deprecated model

GitHub's changelog entry pairs each outgoing model with a suggested alternative. Both retiring Claude models point to the same replacement, while GPT-5.6 Terra has two suggested successors:

Notice that GitHub is consolidating two separate Claude Opus generations — 4.8 and 5 — into a single newer model, Claude Opus 5.5. For GPT-5.6 Terra, GitHub didn't name one single successor; it offered a choice between GPT-6.1 Sol and GPT-6 Luna, leaving the pick to the developer or team depending on which one performs better for their workload. Once enabled, all three replacement models show up directly in the Copilot Chat model selector, so switching is a matter of picking a different entry from a dropdown rather than reconfiguring anything structural.

Why GitHub is retiring these models now

GitHub doesn't spell out a single reason in the changelog beyond routine model-lifecycle management, but the pattern is consistent with how GitHub has handled Copilot's model catalog all year: as model providers ship newer versions, GitHub phases out older ones to keep the supported list from growing indefinitely. GitHub's own supported-models documentation tracks which models currently carry a general-availability status, and retired models are removed from that list once their deprecation date passes.

That documentation page notes that "model availability is subject to change," which is GitHub's standing caveat for exactly this kind of rotation. Developers who've followed Copilot's model changes this year will recognize the shape of this announcement: a new model family arrives, gets folded into Auto and default selection, and the model (or models) it supersedes get a deprecation date a few weeks out.

GitHub has run several rounds of this exact process in 2026. A February 19 changelog update deprecated Claude Opus 4.1, GPT-5, and GPT-5-Codex. An April notice retired GPT-5.1 and its Codex variants. And the September 16 notice mentioned above removed yet another set of models before this one. The November 16 deadline is simply the latest entry in that running series, not a one-off event.

Which Copilot surfaces are affected

GitHub's changelog names four surfaces explicitly: Copilot Chat, inline edits, ask mode and agent mode, and code completions. That covers the large majority of how developers interact with Copilot day to day — conversational chat, in-editor suggestions, and autonomous agent tasks all draw from the same underlying model list, so a model removed from one is removed from all of them simultaneously.

The changelog post does not explicitly mention the Copilot CLI as a named surface in this particular notice. If your team scripts around Copilot CLI with a hardcoded model flag pointing at Claude Opus 4.8, Claude Opus 5, or GPT-5.6 Terra, treat that configuration as at risk too and verify current CLI model support directly against GitHub's documentation rather than assuming it is unaffected.

The Claude Opus 4.8 exception for annual individual plans

There's one carve-out in the announcement: individual Copilot subscribers on annual billing plans keep access to Claude Opus 4.8 even after November 16, specifically so they retain an Opus-family option. GitHub does not extend the same exception to Claude Opus 5 or to GPT-5.6 Terra — both of those are going away for everyone, annual-plan individuals included, on the same date.

If you're on an individual annual plan and relying on Opus 4.8 specifically, you don't need to migrate that particular workflow before the deadline. Everyone else — monthly individual subscribers, and every Business and Enterprise seat — loses access to all three models on November 16 regardless of billing plan.

What happens if you're on Auto or default model selection

For most developers, this deprecation requires no manual action. Anyone using Copilot's default model or the Auto selection setting will be moved onto a supported model automatically; GitHub's changelog is explicit that no action is needed on the user's part in that case, and the same applies to removal of the old models afterward — there's no cleanup step required once November 16 passes.

The people who do need to act are anyone who has hardcoded one of the three retiring model names — Claude Opus 4.8, Claude Opus 5, or GPT-5.6 Terra — into a configuration file, a CI script, a custom Copilot agent definition, an extension, or an MCP-based tool integration. Those references need to be updated to Claude Opus 5.5 or to GPT-6.1 Sol/GPT-6 Luna before the deadline, or the integration will start failing (or silently falling back, depending on how the call is structured) once the old model stops responding.

What Enterprise and Business admins should check

For Copilot Enterprise and Copilot Business customers, GitHub says the suggested replacement models are enabled automatically — unless an administrator has previously turned off the global default for new models, or explicitly disabled a specific model through policy. If your organization has either of those settings in place, Claude Opus 5.5, GPT-6.1 Sol, and GPT-6 Luna will not appear for your users by default, and someone with admin access needs to turn them on manually.

GitHub's documentation on Copilot policies and on how to manage default models for an organization covers exactly where these toggles live: the Models page under an organization's or enterprise's Copilot settings, where each model can be set to enabled or disabled, and where a global default governs whether newly available models turn on automatically. Enterprise customers with specific questions about their rollout are pointed to their GitHub account team in the original changelog post.

How this fits GitHub's recurring Copilot model-lifecycle cadence

This is not the first time Pandromeda has covered a Copilot model deprecation, and it almost certainly won't be the last — GitHub has been retiring and introducing Copilot models on a near-monthly rhythm throughout 2026. We covered the deprecation wave that took effect on October 19, and an earlier one landed on October 2; both involved a different set of models than the ones retiring on November 16, so none of those earlier deadlines affect you if you've already migrated off whatever was deprecated back then. The replacement models named in this latest notice also sit alongside newer additions to Copilot's lineup, including the rollout covered in our look at GPT-6.1 Terra's arrival on Copilot, part of the same broader GPT-6.1 family that includes GPT-6.1 Sol. If you're on GitHub's Free tier of Copilot, it's also worth checking how model availability works on the Free plan, since free usage is typically more restricted than paid individual, Business, or Enterprise seats.

The practical takeaway for engineering teams: Copilot's model roster now turns over roughly as often as a typical dependency does. Anyone maintaining Copilot-adjacent tooling — custom agents, CLI wrappers, CI integrations — should budget for periodic model-name updates the same way they'd budget for a package-version bump, rather than treating each deprecation notice as a surprise.

What to do before November 16

With just over two weeks left before the deadline, here's the practical checklist:

• Check your model selection. If Copilot Chat, inline edits, or agent mode is set to Auto or to GitHub's default, you don't need to do anything — the switch happens automatically.
• Search your codebase and configs for hardcoded model names. Look for "Claude Opus 4.8," "Claude Opus 5," or "GPT-5.6 Terra" in CI pipelines, custom agent definitions, extension settings, or MCP tool configurations, and update any matches to Claude Opus 5.5 or to GPT-6.1 Sol/GPT-6 Luna.
• Admins: confirm your model policy. If your organization has disabled the global default for new models, or specifically blocked one of the replacement models, enable them manually through the Models page in Copilot settings before the deadline so your users aren't left without a working model.
• Annual individual subscribers: if you specifically rely on Claude Opus 4.8, note that you keep it — but Claude Opus 5 and GPT-5.6 Terra still go away for you on the same date as everyone else.
• Double-check the Copilot CLI separately. Since the changelog doesn't name CLI explicitly among the affected surfaces, verify any CLI-specific model configuration against GitHub's current documentation rather than assuming it's covered or exempt.

None of this requires urgent same-day action, but waiting until November 16 itself risks a broken build pipeline or a Copilot agent that silently stops responding mid-task. The safest move is to treat the next two weeks as a migration window rather than the night before the change.

Written byFelix Moreau

Felix Moreau writes Pandromeda's software coverage and how-to guides. He covers Windows, macOS and Linux updates, the apps people rely on, emulators and developer tools, and turns official documentation into clear, numbered steps that work on the current version.

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