Gemini 3.7 Flash and 3.5 Flash are deprecated, and the old Deep Research agent shuts down on October 23, 2026

What you get

The Gemini API changelog entry for October 8, 2026 lists three deprecations.

gemini-3.7-flash is deprecated and replaced by gemini-3.8-flash. Requests to it are automatically routed to gemini-3.8-flash.
gemini-3.5-flash is deprecated and replaced by gemini-3.6-flash. Requests to it are automatically routed to gemini-3.6-flash. The changelog says you can move to gemini-3.6-flash or gemini-3.8-flash.
The deep-research-pro-preview-12-2025 agent is deprecated and will be shut down on October 23, 2026. The changelog names deep-research-preview-04-2026 and deep-research-max-preview-04-2026 as the agents to move to.

The deprecations page shows "No shutdown date announced" for both Flash models.

Prerequisites

A Gemini API key in GEMINI_API_KEY
An app that calls one of the three names above

Steps

Search your code and settings for gemini-3.7-flash, gemini-3.5-flash and deep-research-pro-preview-12-2025.
Replace gemini-3.7-flash with gemini-3.8-flash. Replace gemini-3.5-flash with gemini-3.6-flash or gemini-3.8-flash. Change only the model name.
For Deep Research, change the agent value in your interactions.create requests to deep-research-preview-04-2026 or deep-research-max-preview-04-2026. Do this before October 23, 2026.
Because the Flash requests are already routed to the newer models, compare a few of your usual prompts and check the answers still suit your app.

Test it

Send one normal request with each new name and confirm you get an answer with no error. Search your project once more to confirm the old names are gone.

Not confirmed