# Gemini 2.5 Pro Drops to Avoid: Google Deprecates 2.5 Pro and 2.5 Flash and Reroutes Their Requests on 1 December

Google deprecated gemini-2.5-pro and gemini-2.5-flash on 2 November, and from 1 December 2026 their API requests route to gemini-3.8-flash and gemini-3.5-flash-lite, billed at those models' rates and with breaking API changes. We are moving Gemini 2.5 Pro from conditional to avoid: migrate now, before the switch does it for you.

By Neomanex. Updated 2026-11-03.

**Verdict: [Gemini 2.5 Pro](/models/gemini-25-pro) moves from conditional to avoid.** Google deprecated it on 2 November 2026, and from 1 December 2026 a request that names `gemini-2.5-pro` is answered by [Gemini 3.8 Flash](/models/gemini-3-8-flash) and billed at Gemini 3.8 Flash rates. That is 28 days from 3 November. Migrate on your own schedule now, rather than let Google swap the model under a live pipeline.

On 23 October we moved 2.5 Pro to conditional because Google's page said the 2.5 models were "not deprecated" and listed no shutdown date. Both of those facts are now gone, so the verdict moves with them. The same change hits Gemini 2.5 Flash, which is not in our directory.

## What happened

Google's [Gemini API changelog](https://aistudio.google.com/docs/changelog), entry dated 2 November 2026:

> "`gemini-2.5-pro` is deprecated and is no longer available to select in Google AI Studio. Effective December 1, 2026, all API requests to `gemini-2.5-pro` will automatically route to `gemini-3.8-flash` and be billed at Gemini 3.8 Flash rates."

The entry for `gemini-2.5-flash` uses the same wording: requests "will automatically route to `gemini-3.5-flash-lite`" and are "billed at Gemini 3.5 Flash-Lite rates". Both entries tell developers: "Before December 1, 2026, update your model string" to the new model and review its migration guide.

Google's [deprecations page](https://aistudio.google.com/docs/deprecations) now gives both `gemini-2.5-pro` and `gemini-2.5-flash` a shutdown date of December 1, 2026, with `gemini-3.8-flash` and `gemini-3.5-flash-lite` as the replacements. `gemini-2.5-flash-lite` still shows "No shutdown date announced".

What this is not: a hard shutdown. Requests to the old ids keep getting answers after 1 December. They just come from a different model, at a different price.

## Why it matters

- **Your app changes model without a deploy.** After 1 December, code that still says `gemini-2.5-pro` gets Gemini 3.8 Flash. Output, latency and token use can all shift, and nothing in your code will show it.
- **Your bill changes too.** Rerouted requests are billed at the new model's rates. We did not read Google's pricing page for this post, so check the current rates for both replacements before you budget.
- **Some requests may fail.** Google's changelog says: "Breaking API changes include function calling and `thought_signature` validation, `thinking_level` replacing `thinking_budget`, and removed sampling parameters and prefilled model turns." A request that works on 2.5 today can be rejected after the switch.
- **No more new projects.** 2.5 Pro and 2.5 Flash can no longer be selected in Google AI Studio.

## What changes for you

| | Before (23 October) | Now |
|---|---|---|
| Rating | Conditional | Avoid |
| Google's status | "Not deprecated", no shutdown date | Deprecated, shutdown date 1 December 2026 |
| Right for | Existing pipelines that already call it | Nobody: migrate before 1 December |

We have not run 2.5 Pro against 3.8 Flash, or 2.5 Flash against 3.5 Flash-Lite, on our own workloads. Test your own prompts on the replacement before you switch, and fix any request that still sets `thinking_budget`, sampling parameters or a prefilled model turn.

## FAQ

**Does gemini-2.5-pro stop answering on 1 December?**
No. Requests keep getting answers, but from Gemini 3.8 Flash, billed at Gemini 3.8 Flash rates.

**Is Gemini 2.5 Flash-Lite affected?**
Not yet. Google's deprecations page still lists "No shutdown date announced" for `gemini-2.5-flash-lite`.

**Can I still pick 2.5 Pro in Google AI Studio?**
No. Google says both 2.5 Pro and 2.5 Flash are no longer available to select there.

Canonical: https://neomanex.com/news/gemini-2-5-pro-flash-deprecated-auto-route-dec-1-avoid