By ByteBot
GitHub deprecated Gemini 2.5 Pro and Gemini 3 Flash across all Copilot experiences on July 31 — no grace period, no fallback. If you were using either model in VS Code, JetBrains, Xcode, the Copilot CLI, or Copilot Chat on the web, they are gone. This is the sixth model deprecation in Copilot since January 2026. The pattern is no longer surprising. The pace is.
What to Migrate To
GitHub’s own July 31 changelog told developers to switch to Gemini 3.1 Pro or Gemini 3.5 Flash. The better answer for most teams is Gemini 3.6 Flash, which shipped in Copilot on July 21 — ten days before the deprecation — and is strictly better than 3.5 Flash. Here is the replacement map:
| Deprecated | Best Replacement | Why |
|---|---|---|
| Gemini 2.5 Pro | Gemini 3.1 Pro | 1M token context, stronger reasoning |
| Gemini 3 Flash | Gemini 3.6 Flash | Configurable reasoning, 17% fewer output tokens |
| Either | Auto mode | Future-proof, no manual switching needed |
Gemini 3.6 Flash added something 3.5 Flash lacked: configurable reasoning effort, similar to how o1-style chain-of-thought works. For agentic tasks, that matters. Google reports up to 65% token reduction in some agentic workflows versus its predecessor, with pricing dropping to $1.50 per million input tokens and $7.50 per million output.
How to Switch
In VS Code, open Copilot Chat, click the model picker, and select your replacement. In JetBrains (version 1.5.62+), the picker is in Ask, Edit, and Agent modes. Enterprise admins need to enable the model in Settings → Copilot → Model Policies before users can see it in their IDEs.
For the Copilot CLI, the cleanest path is Auto mode. Run gh copilot suggest and select Auto — it routes based on task complexity, honors your admin’s model policies, and automatically avoids deprecated models. There is a known bug: Gemini 3.1 Pro does not appear in the CLI model list even when enabled at the org level (github/copilot-cli #1703). Until that is fixed, Auto mode is the safer choice for CLI users.
JetBrains users have a separate issue: the deprecation warning was never surfaced in the model picker UI (copilot-intellij-feedback #1886). If you use IntelliJ or another JetBrains IDE, you may not have seen this coming.
Six Deprecations in Seven Months
This is not random churn. GitHub has deprecated Copilot models roughly every four to six weeks since January: legacy Claude and OpenAI models in January, Gemini 3 Pro in March, Claude Sonnet 4 in May, GPT-4.1 and GPT-5.2 in June, and now Gemini 2.5 Pro and Gemini 3 Flash. The lesson is the same each time: do not pin specific model names in scripts, configs, or CI pipelines. Use Auto mode. GitHub’s Auto mode routes across providers based on task complexity, real-time model health, and admin policy — it will not route you to a deprecated model.
Enterprise: Two More Changes Shipped the Same Day
GitHub shipped two additional enterprise governance features on July 31.
The first is enterprise teams model policy targeting, now in public preview for Copilot Business and Enterprise customers. Until now, model access was controlled at the organization level. The new feature lets admins grant different model access to specific enterprise teams — for example, giving an AI research team Gemini 3.1 Pro while the rest of the organization stays on cheaper models. GitHub has said this is “the first step in a broader shift toward team-level governance.”
The second is a default model enablement policy change announced July 29 and effective August 26. Going forward, generally available models will be enabled by default on Business and Enterprise plans — meaning new models appear without admin action. If your enterprise needs strict model governance, you now need to opt out rather than opt in. Enterprise admins should audit their model policies before August 26.
What to Do Right Now
- Open your model picker, replace Gemini 2.5 Pro with Gemini 3.1 Pro, and replace Gemini 3 Flash with Gemini 3.6 Flash — or enable Auto mode and stop tracking this entirely.
- If on an enterprise plan, verify your admin has enabled the replacement models. The new default enablement policy does not retroactively enable Gemini 3.1 Pro or 3.6 Flash if your admin previously disabled all Gemini models.
- Check whether the August 26 default enablement policy requires any action for your org’s governance posture.
- Consider whether enterprise team-level policy targeting is useful for your org’s model access strategy.
The model rotation is not slowing down. Build your Copilot workflows around that fact.
