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gemini-2.5-pro on Gemini API is routed to gemini-3.8-flash on December 1, 2026

AI model

Date
(UTC)
Replacement
gemini-3.8-flash
Platform
Gemini API
Provider
Google
Last checked

gemini-2.5-pro

Routes to gemini-3.8-flash on Gemini API

In its place: gemini-3.8-flash

since.dev/calendar/google/gemini-2.5-pro/gemini

What changes

Requests keep working, answered by gemini-3.8-flash.

What works differently on gemini-3.8-flash

From its documentation. Moving to it is more than a new model ID.

  • Default thinking level is MEDIUM; supported thinking levels are LOW, MEDIUM, HIGH. To keep the old behavior: set thinking_level explicitly if the code relied on a different reasoning level. Source
  • Explicitly setting thinking_level to MINIMAL returns an API validation error. To keep the old behavior: do not set thinking_level to MINIMAL; use LOW, MEDIUM, or HIGH. Source
  • Prefilled model turns are unsupported and must be removed when upgrading. To keep the old behavior: remove prefilled model turns from conversation histories. Source
  • Integer thinking_budget configurations are replaced by the string enum thinking_level. To keep the old behavior: replace thinking_budget with the string enum thinking_level. Source
  • Passing frequency_penalty or presence_penalty throws an active API error. To keep the old behavior: remove frequency_penalty and presence_penalty from legacy client code. Source
  • History payloads cannot end with a model role turn. To keep the old behavior: ensure conversation history does not end with a model role turn. Source
  • A FunctionResponse turn must strictly match the id, name, and execution count of the preceding FunctionCall. To keep the old behavior: make each FunctionResponse match the id, name, and execution count of the preceding FunctionCall. Source

Source

aistudio.google.com

gemini-2.5-pro | June 17, 2025 | December 1, 2026 | gemini-3.8-flash (gemini-2.5-pro is no longer available in Google AI Studio; effective December 1, 2026, API requests to gemini-2.5-pro will automatically route to gemini-3.8-flash)

Data license: CC BY 4.0. From Google's documentation. Quotes are shortened and dates restated.

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