Nex claims viral Rio 3.5 model is a re-skin of its open-source Nex-N2-Pro
On 14 June 2026, NexDealroom has a profile for this one. Try Dealroom → claimed that the viral Rio 3.5 Open 397B model, published by Rio de Janeiro's municipal IT authority IplanRIODealroom has a profile for this one. Try Dealroom →, is largely derived from its open-source Nex-N2-Pro model. In a post on X, Nex said it had analysed the model weights and concluded that Rio 3.5 was created through a combination of approximately 60% Nex-N2-Pro and 40% Qwen 3.5, the open-weight model developed by Alibaba Cloud. The company also claimed that Rio 3.5 identifies itself as Nex-N2-Pro when prompted.
The claim follows the rapid rise of Rio 3.5 within the AI community after the model was released on Hugging Face as an open-weight, multimodal large language model. According to its model card, Rio 3.5 incorporates both Qwen 3.5 and Nex-N2-Pro, followed by additional distillation and optimisation steps.
Nex-N2-Pro is the flagship model of Nex, an open-source agentic AI ecosystem initiated by the Shanghai Innovation Institute. The model uses a mixture-of-experts architecture with 17 billion active parameters out of 397 billion total. The debate highlights the increasingly blurred boundaries of attribution in the open-model ecosystem, where models are frequently merged, distilled and redistributed under new identities.
Read more: Nex on X
