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GoogleDeprecation

gemini-2.5-pro, gemini-2.5-flash

Deprecation, announced 18 September 2026. Plan a migration: Check whether any project still calls a Gemini 2.5 model id, and open a migration ticket for the ones that do before new projects lose access.

What Google says changed

Google limited access to Gemini 2.5 models to projects that are actively using them. The entry points developers to Gemini 3.5 Flash-Lite or Gemini 3.8 Flash instead.

Google: Gemini API changelog

announced 2026-09-18 . verified 2026-09-22

This section restates the provider. It adds no judgement the provider did not make, and it contains no measurement of ours.

Entry

Provider
Google
Models
gemini-2.5-pro, gemini-2.5-flash
Change type
Deprecation
Announced
2026-09-18
Verified
2026-09-22

What this kind of change typically touches

  • Chat assistant

    A forced move changes the model behind every answer. Google's own documentation says most production apps should use a specific stable model, and hedges only that stable models usually do not change.

    Google

  • RAG

    When the generating model is replaced, the answer is scored again for faithfulness, which Ragas defines as the share of claims in a response that can be inferred from the retrieved context. It scores grounding in that context, not factual truth.

    Ragas

What to do this week

Plan a migration

Check whether any project still calls a Gemini 2.5 model id, and open a migration ticket for the ones that do before new projects lose access.

If you are on a plan

A tracked provider update triggers a rerun of your suite within 2 business days of the announcement, and you get a written verdict. That is one of the six guarantees on every plan.

See plansRead EV-RERUN

Other Google changes

GoogleNew version

gemini-3.8-flash

Google released gemini-3.8-flash as generally available. The entry states it brings improvements for long horizon software engineering.

Rerun the suiteQueue gemini-3.8-flash into the next comparison run against the Flash model you use now, and record the result before moving traffic.

Source: Google, Gemini API changelog . verified 2026-09-22

GoogleNew version

gemini-3.7-flash

Google released gemini-3.7-flash. The entry states it brings substantial improvements across software engineering.

Rerun the suiteAdd gemini-3.7-flash to the comparison run you already schedule for Flash tier models, and note where its answers differ from the version you pin.

Source: Google, Gemini API changelog . verified 2026-09-22

GoogleNew version

gemini-3.6-flash, gemini-3.5-flash-lite

Google released gemini-3.6-flash and gemini-3.5-flash-lite as generally available. The same entry deprecates the sampling parameters temperature, top_p and top_k.

Revisit the promptSearch your request builders for temperature, top_p and top_k on Gemini calls and plan their removal, then rerun the affected cases with the parameters dropped.

Source: Google, Gemini API changelog . verified 2026-09-22

Questions

How do I know this is accurate?
The entry links to Google's own page, and the date we read it is on this page. If the provider's page and this page disagree, the provider's page is right and we want to hear about it.
Does this mean my feature broke?
No. It means a thing your feature depends on changed. Whether anything about your output changed is a question only a rerun against your own dataset can answer, and that is what the recommended action is for.
Why is there no score or benchmark here?
Because we publish none. This site restates provider announcements and cites published practitioner guides. Any measurement we make belongs to the customer whose dataset produced it.

Sources

Change-log entries restate provider announcements with sources and dates. Impact notes cite public practitioner reports. The site publishes no measurements of its own on any model.

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