In the gemini iOS app the only available models are currently 2.0 flash and 2.0 flash thinking.
I think the "AI Premium" plan of Google One includes access to all the models, including the latest ones (at least that's what it says for me in Spain): https://one.google.com/plans
In the gemini iOS app the only available models are currently 2.0 flash and 2.0 flash thinking.