API: from 21 November, both Simba 1.6 ids are served and billed as Simba 3.5

When the Simba 1.6 trainings stop serving on 21 November 2026, requests that still name simba-english or simba-multilingual go to Simba 3.5 in every language, English included. The 2026-09-21 entry named simba-3.2 for English text on simba-english; Simba 3.5 is the model we recommend, and it is the model you hear when you test simba-3.5 today.

Both ids bill as simba-3.5. A request naming either id is billed at the simba-3.5 rate on your plan; see pricing.
Nothing breaks. Both ids keep answering on every API version that can still name them, and the audio changes.
To choose the model yourself, set model to simba-3.5 before the date, or simba-3.2 if your text is English only, which keeps today’s price.

The migration guide has the details.