There are some "leaks" here and there ("forgotten" strings in AI Studio) and A/B-testing with nano-banana-2/nano-banana-pro so it will definitely come very soon. Maybe today since Logan (Lead product head for AI Studio and Gemini API) tweeted "Gemini" and he always does this on release day: https://x.com/OfficialLoganK/status/1990633642478219706

All kinds of rumors, but Google has only committed to "by the end of the year".