Breaking model
gemini-2.5-flash-lite-preview-09-2025 was shut down on the Gemini API March 31, 2026; the current listed replacement is gemini-3.1-flash-lite.
What changes
Google announced on March 10, 2026 that the model would shut down March 31, 2026, and the changelog records it as shut down that day. The changelog entry pointed to gemini-3.1-flash-lite-preview, which was itself shut down May 25, 2026; the deprecations page now lists gemini-3.1-flash-lite.
Breaking: Calls fail after this date.
What to do
Switch to gemini-3.1-flash-lite, not gemini-3.1-flash-lite-preview. The deprecations page lists May 7, 2027 as its earliest shutdown date, with gemini-3.5-flash-lite as the replacement after that. Re-check output quality on your evals.
Strings to search for
gemini-2.5-flash-lite-preview-09-2025