TL;DR: GitHub Copilot retired 10 models in October 2026 — four on October 2, six on October 19 — and retires Claude Opus 4.8, Claude Opus 5, and GPT-5.6 Terra on November 16. Replacements are auto-enabled for Business and Enterprise only if your admin hasn’t disabled the global model default. On a $10 Pro plan, GitHub’s suggested replacement for GPT-5.5 isn’t even available to you.

	Individual on Pro/Pro+	Business/Enterprise admin	BYOK in Cursor/Cline
What breaks	Your selected model vanishes from the picker	Pinned org models stop working; replacements may not be enabled	Nothing — Copilot retirements don’t touch API-key setups
What to do	Switch to the mapped replacement below	Check model policies in Copilot settings before Nov 16	Nothing now; watch the provider’s own API deprecations
The catch	GPT-6.1 Sol needs Pro+ ($39/mo); Pro gets GPT-6 Luna	Auto-enablement skips models you explicitly disabled	Policy controls don’t extend to BYOK models anyway

Honest take: Treat the November 16 wave as your deadline to stop pinning model IDs at all — that’s three Copilot retirement waves in six weeks, and GPT-5.6 Terra lasted 130 days. Pick the newest default, keep one fallback enabled, and put the model name in one config file, not twenty.

A note on sourcing: github.blog and docs.github.com would not load directly from the environment this was researched in, so every changelog entry below is cited from GitHub’s own changelog URLs as surfaced through search, cross-checked against at least two independent writeups. The replacement names conflict across third-party coverage (several outlets still say “GPT-5.6 Sol” — that’s the September announcement, superseded by retirement day). Where sources disagreed, the official changelog table wins, and the disagreement is flagged.

Which GitHub Copilot models were retired in October 2026?

Ten models left Copilot in October 2026, in two waves. On October 2, GitHub deprecated four models across all Copilot experiences — Chat, inline edits, ask and agent modes, and code completions (changelog, Oct 2, 2026):

Retired Oct 2, 2026	GitHub’s suggested replacement
Gemini 3.5 Flash	Gemini 3.8 Flash
Gemini 3.6 Flash	Gemini 3.8 Flash
Kimi K2.7 Code	Kimi K3
Claude Opus 4.7	Claude Opus 5.5

On October 19, six more followed — the wave GitHub had announced on September 18 (changelog, Oct 19, 2026; announcement, Sep 18, 2026):

Retired Oct 19, 2026	GitHub’s suggested replacement
GPT-5.5	GPT-6.1 Sol
GPT-5.4	GPT-6.1 Sol
GPT-5.4 mini	GPT-6 Luna
GPT-5 mini	GPT-6 Luna
Gemini 3.7 Flash	Gemini 3.8 Flash
Grok 4.5	Grok 4.7

Both changelog entries state no action is required to remove the deprecated models — they simply disappear from the model picker. The action is on the replacement side, covered below.

One detail that shows how fast this treadmill spins: GitHub’s September 18 heads-up named GPT-5.6 Sol and Grok 4.6 as the replacements. By the time the retirement actually landed 31 days later, both suggested replacements had themselves been superseded — the final October 19 table points at GPT-6.1 Sol and Grok 4.7 instead. Several news sites ran the September names, which is why you’ll find “Copilot retires 6 models for GPT-5.6” headlines that no longer match GitHub’s own table.

Which models leave GitHub Copilot on November 16, 2026?

Three models: Claude Opus 4.8, Claude Opus 5, and GPT-5.6 Terra, per GitHub’s October 15 changelog (Upcoming deprecation of selected GitHub Copilot models in mid-November):

Retired Nov 16, 2026	GitHub’s suggested replacement
Claude Opus 4.8	Claude Opus 5.5
Claude Opus 5	Claude Opus 5.5
GPT-5.6 Terra	GPT-6.1 Sol or GPT-6 Luna

There is one carve-out: individual Copilot subscribers on annual plans keep access to Claude Opus 4.8 past November 16. The exception does not extend to Business or Enterprise seats — those should move to Claude Opus 5.5.

GPT-5.6 Terra’s lifespan is worth pausing on. It entered Copilot on July 9, 2026 (changelog) and exits November 16 — 130 days. If your team standardized on Terra for long agent runs in August, you got about one quarter out of that decision.

Does your Copilot plan actually include the suggested replacement?

Not necessarily, and this is the trap in GitHub’s replacement table. GPT-6 Sol and GPT-6 Luna arrived in Copilot on September 22, 2026, and GPT-6.1 Sol followed on September 29 (changelog, Sep 22; changelog, Sep 29). Plan access per those entries:

• GPT-6.1 Sol / GPT-6 Sol: Copilot Pro+ ($39/mo), Max ($100/mo), Business ($19/seat), Enterprise
• GPT-6 Luna: all of the above plus Copilot Pro ($10/mo)

So a Pro subscriber who was using GPT-5.5 gets pointed at GPT-6.1 Sol by the deprecation notice but can’t select it — on $10/month, the real replacement is GPT-6 Luna, which OpenAI positions as the lightweight, cost-efficient end of the GPT-6 family. If Luna isn’t enough for your agent workloads, your options are upgrading to Pro+ or routing around Copilot entirely with GPT-6.1 Sol via BYOK in Cursor or Cline. Both GPT-6 models bill through usage-based AI Credits, the system Copilot moved to on June 1, 2026 — the mechanics are in our AI Credits billing breakdown.

Plan prices above match what GitHub listed when we verified the lineup on September 21, 2026 (Free $0 / Pro $10 / Pro+ $39 / Max $100 / Business $19 per seat) and October 2026 third-party pricing trackers agree; confirm on github.com/features/copilot/plans before buying.

Does Copilot switch you to the replacement automatically?

For Business and Enterprise: the suggested replacements are enabled automatically under Copilot’s default model enablement — unless an administrator turned off the global default or explicitly disabled that specific model, in which case the replacement must be enabled manually through model policies in Copilot settings. That’s GitHub’s own wording across the October changelog entries, and it follows from the model-policy change GitHub shipped in late August 2026, when unconfigured models flipped to on-by-default for enterprise users.

The failure mode we’d plan around: an org that locked its model list down in August (global default off, a short allowlist of approved models) hits Monday, November 16 with Claude Opus 5 gone, Claude Opus 5.5 not on the allowlist, and every developer who had Opus 5 selected staring at a model picker with no equivalent in it. Nothing errors loudly — the model is just absent. The fix takes an admin two minutes: Copilot settings → Models (model policies) → enable Claude Opus 5.5 — but only if someone does it before the 16th rather than during the Monday-morning Slack flood. If you administer a locked-down org, check the policy list against the three November names today.

For individual Pro and Pro+ subscribers there’s no policy layer: the retired model disappears from the picker and you pick a new one. Community reports differ on what clients do when a retired model is still named in a saved configuration — silent fallback to default or an error depending on the integration — and GitHub doesn’t document this behavior, so don’t rely on either.

How do you find hardcoded retired model IDs before they bite?

Grep for them. Model names end up pinned in VS Code workspace settings, CI jobs that call agent CLIs, and team dotfiles, and those are the references nobody remembers until a pipeline fails:

$ grep -rniE 'gpt-5\.5|gpt-5\.4|gpt-5 ?mini|gemini-3\.[567]|grok-4\.5|opus-(4\.[78]|5)\b|gpt-5\.6|kimi-k2' \
    --include='*.json' --include='*.yml' --include='*.yaml' --include='*.toml' .

.vscode/settings.json:14:    "github.copilot.chat.model": "gpt-5.5"
.github/workflows/review.yml:23:        model: claude-opus-5

Every hit is a config that either already broke in October or breaks November 16. Swap each one for the mapped replacement from the tables above, and while you’re in there, ask whether that pin needs to exist — after three retirement waves in six weeks, a hardcoded Copilot model ID is a scheduled outage.

Do the retirements affect BYOK setups in Cursor or Cline?

No. These deprecations remove models from GitHub Copilot’s hosted picker; they say nothing about the models’ availability on OpenAI’s, Anthropic’s, Google’s, or xAI’s own APIs, which retire on their providers’ schedules. If you run Gemini 3.8 Flash or Kimi K3 through your own API key in Cursor or Cline, October 19 changed nothing for you. GitHub’s enterprise model policy doesn’t govern BYOK models either — a point admins have raised in GitHub’s community discussions — so policy lockdowns neither protect nor break key-based setups.

The fully retirement-proof version of this is a local model: an open-weight coding model served from your own hardware can’t be deprecated out from under you. Copilot itself can front local Ollama models in VS Code; hardware sizing for that lives at runaihome.com, and self-hosted FOSS alternatives like Tabby are covered at aifoss.dev.

Why is GitHub retiring models this fast?

Because the economics upstream moved. OpenAI priced the GPT-6 family roughly 50% below equivalent GPT-5.x API rates at its September 22 launch (VentureBeat’s launch coverage), and Copilot now bills model usage through AI Credits — so every request served on an older, pricier model is margin GitHub donates to nostalgia. Mapping two retired GPT-5.x models onto one Sol tier and two minis onto one Luna tier also shrinks the support matrix GitHub has to test agent mode against.

The cadence since summer: GPT-5.6 Sol/Terra/Luna added July 9; a six-model retirement announced September 18; four models out October 2; six more October 19; three more November 16. GPT-6 Sol was superseded by GPT-6.1 Sol seven days after it reached Copilot. None of this is slowing down, and the practical conclusion isn’t “GitHub is being hostile” — it’s that model identity is now infrastructure that churns quarterly, and your tooling should treat it like a dependency with a lockfile you expect to bump, not an architectural decision.

Which replacement should you pick?

Your situation	Pick	Plan needed	Why
You were on GPT-5.5/5.4 for agent work	GPT-6.1 Sol	Pro+ $39/mo or Business	GitHub’s mapped replacement; balanced interactive + agentic model
You were on GPT-5.5 but pay $10 Pro	GPT-6 Luna	Pro $10/mo	Sol isn’t offered on Pro; Luna is the only GPT-6 you can select
You were on Claude Opus 4.8/5	Claude Opus 5.5	Per your current plan’s model list	GitHub’s mapped replacement for both Opus retirements
You were on any retired Gemini Flash	Gemini 3.8 Flash	Per your current plan	Single replacement for 3.5/3.6/3.7 Flash
You pin models in CI or team configs	Stop pinning; set default + one fallback	—	Three retirement waves in six weeks; pins are scheduled outages
You want out of the churn entirely	Local model via Ollama BYOK	$0 software	Can’t be deprecated; needs your own GPU (see runaihome.com)

FAQ

Is this the same thing as the “Copilot retires 6 models for GPT-5.6” story? Same event, outdated details. That framing comes from GitHub’s September 18 announcement, which named GPT-5.6 Sol as the replacement. The actual October 19 retirement table names GPT-6.1 Sol and Grok 4.7 — and GPT-5.6 Terra is itself retired on November 16.

Do I lose chat history or custom instructions when my model is retired? The changelogs describe removing models from Copilot experiences, not touching conversations or instruction files. Your repository custom instructions are model-agnostic and carry over to whatever you select next.

I’m an individual annual subscriber — do I really keep Claude Opus 4.8? Per the October 15 changelog, yes: individual subscribers on annual plans retain Opus 4.8 access past November 16, 2026. Monthly individuals and all Business/Enterprise seats don’t.

Will the replacement model cost more per request? GPT-6 family API pricing launched at roughly half of GPT-5.x equivalents, and in Copilot both Sol and Luna bill through usage-based AI Credits. Whether your monthly credit burn drops depends on your mix; the billing mechanics are in our AI Credits guide.

How do I know this won’t happen again in December? You don’t — assume it will. GitHub announced the October 19 wave 31 days ahead and the November 16 wave 32 days ahead, so watch github.blog/changelog monthly and keep model names out of anything that can’t be changed in one place.

Sources

• GitHub Copilot models deprecated on October 19, 2026 — GitHub Changelog
• Selected models in GitHub Copilot deprecated (Oct 2 wave) — GitHub Changelog
• Upcoming deprecation of selected GitHub Copilot models in mid-November — GitHub Changelog, Oct 15, 2026
• Upcoming deprecation of selected GitHub Copilot models in mid-October — GitHub Changelog, Sep 18, 2026
• OpenAI’s GPT-6 Sol and GPT-6 Luna now available — GitHub Changelog, Sep 22, 2026
• GPT-6.1 Sol in GitHub Copilot — GitHub Changelog, Sep 29, 2026
• OpenAI’s GPT-5.6 Sol, Terra, and Luna are now available in GitHub Copilot — GitHub Changelog, Jul 9, 2026
• OpenAI releases GPT-6 Sol and Luna models, slashing API costs 50% or more — VentureBeat
• GitHub Copilot Model Policy Goes Live: Unconfigured AI Models Now On by Default for Enterprise Users — Tech Times, Aug 27, 2026
• GitHub Copilot to sunset 3 models including Claude Opus 5 on November 16 — AI Trend Lab
• Copilot models policy update — default on and enterprise teams targeting — GitHub Community Discussion #203163
• GitHub Retires Six Copilot Models: Replacement Map and Enterprise Policy Checks — WindowsForum

Last verified October 23, 2026. Model lineups and plan gates change monthly — GitHub’s changelog is the authority; re-check before changing org policy.

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