Rio de Janeiro's city government shipped a 397B open model under MIT.

IplanRIO released Rio 3.5 Open 397B on Hugging Face, a sparse MoE (~17B active) post-trained from Qwen 3.5 397B, ~1.01M-token context, multimodal (Hugging Face). It introduces SwiReasoning, a training-free inference framework that switches between explicit chain-of-thought and latent-space reasoning via entropy-based confidence signals. A municipal IT company shipping a frontier-class open model is the kind of thing I didn't have on my bingo card. Benchmark claims still await independent audit, so file under "remarkable if it holds."