Upstage said on the 23rd that it has unveiled "Solar Open 2," its latest large language model (LLM) developed through participation in the government's "independent AI foundation model" project.
Built on its previous model "Solar Open," the new model features usability optimized for AI agents that complete tasks from start to finish by repeating dozens of rounds of inference and tool calls. Solar Open 2 has a total of 250 billion parameters but uses a mixture-of-experts (MoE) architecture that activates only the 15 billion needed for actual tasks. The design aims to add efficiency to AI agent tasks that consume large numbers of tokens. It can handle long task content of up to 1 million tokens, allowing it to maintain task history while processing vast document workloads. When quantization is applied, it runs on two Nvidia H200 graphics processing units (GPUs), reducing the cost burden for companies deploying it on their own infrastructure.
Upstage said Solar Open 2's various AI benchmarks exceed those of DeepSeek's "V4 Flash." It also outperformed V4 Flash, Mistral's "Medium 3.5," and Cohere's "Command A+" in benchmarks covering comprehensive knowledge (MMLU-Pro), coding (LiveCodeBench), instruction following (IFBench), tool calling (MCP-Atlas), and comprehensive AI agent evaluation (APEX-Agents). In the overall average of Korean-language benchmarks, it received higher scores compared with OpenAI's "GPT-5.4 mini" and Anthropic's "Claude Haiku 4.5."
Upstage plans to apply Solar Open 2 to the Daum portal site to offer a conversational AI agent public service. It will also help local governments and public and educational institutions nationwide easily adopt AI agents through its AI agent platform "Timely."
The company is also accelerating the spread of industrial AI transformation (AX). Upstage will fully launch Solar Open 2-based AX services across all industrial sectors together with companies in its independent foundation model consortium. "Solar Open 2 is a model built with an emphasis on the usability of AI agents that complete work on their own in real workplaces," said Kim Sung-hoon, CEO of Upstage.
