Nano Banana 2 does not immediately replace the original Nano Banana model; both are available simultaneously during a transition period. The original model remains accessible through the API using its existing model identifier, so applications built on the first version continue to work without any code changes. This parallel availability is intentional—it gives development teams time to evaluate Nano Banana 2's output quality against the original, run their own regression tests, and migrate on their own schedule rather than being forced to update by a hard deprecation deadline.
That said, the original Nano Banana model is in maintenance mode, meaning it receives security patches but not new features or quality improvements. New capabilities—such as support for additional aspect ratios, improved text rendering, and expanded style guidance parameters—are available only in Nano Banana 2. If your application relies on any of these features, or if you want to benefit from ongoing quality improvements, migrating to Nano Banana 2 is necessary. The API changelog documents the specific additions that are exclusive to version 2.
The original model will eventually be deprecated and removed, with a minimum notice period published in advance. The deprecation timeline is typically announced at least six months before the end-of-life date, giving teams ample time to complete migration. In most cases, migrating from the original to Nano Banana 2 requires only changing the model identifier string in the request, though it is worth running a sample of your production prompts through both models to catch any cases where the output style has shifted enough to affect your application's output quality expectations.