In a note dated 18 September Google limited access to the Gemini 2.5 models in the API to users who have actively used them. They are not deprecated, but for a new app Google points to 3.5 Flash-Lite or 3.8 Flash, citing capacity.
- The 2.5 models keep working for their existing users until further notice.
- For new projects Google recommends 3.5 Flash-Lite or 3.8 Flash.
- The note does not say who exactly counts as an existing user.
Four sentences in the API release notes. That is how the most important changes sometimes arrive.
If you started a project on Gemini 2.5 and have not shipped it yet, the check is today.
The word “capacity” is the key. The company does not say the models are weak or unsafe. It talks about reliable performance and capacity. Our inference: 2.5 was not closed for quality but for space.
What is unclear is who exactly “has actively used them in the past”. A new API key in the same account? A new project in the same organisation? The note does not say. If you rely on 2.5 for something you are about to bring up on a new key, test it before it becomes urgent.
Moving to 3.8 Flash is not changing one name in the code. A different model gives different answers to the same prompt, and everything you tuned by hand has to be checked again.