# Upstage's Solar Open2 arrives as a 250B MoE model

> The Korean AI firm's latest open release scales to 250 billion parameters with a mixture-of-experts design tuned for English and Korean.

Published by The Open Weights on Jul 22, 2026. Canonical: https://theopenweights.com/news/solar-open2-250b-fhuj

## Key facts

- Company: Upstage
- Model: Solar Open2 250B
- Version: Open2
- Category: Text / LLM
- Modalities: Text / LLM
- License: Other (Open weights, commercial use allowed)
- Parameters: 250B (mixture of experts)
- Context window: 1.0M tokens
- Architecture: SolarOpen2ForCausalLM
- Precision: BF16
- Weights size: 500.6 GB
- Significance: notable
- Published: 2026-07-22
- Last verified: 2026-08-05
- Hugging Face: https://huggingface.co/upstage/Solar-Open2-250B
- Canonical URL: https://theopenweights.com/news/solar-open2-250b-fhuj

Upstage has released Solar Open2 250B, a text-generation model built on a mixture-of-experts (MoE) architecture and made available on [Hugging Face](https://huggingface.co/upstage/Solar-Open2-250B). The release marks a notable step up in scale for the Korean company's open Solar line, which has focused on delivering competitive language models outside the largest US labs.

The headline figure is a 250-billion-parameter footprint. As an MoE system, the model routes each token through a subset of specialized expert networks rather than activating every parameter at once — an approach that lets developers pursue large total capacity while keeping inference costs more manageable than a comparably sized dense model.

## Bilingual by design

Solar Open2 is aimed squarely at English and Korean workloads. That bilingual focus has been a consistent thread for Upstage, whose earlier Solar models earned attention for punching above their size, and it positions the release as a practical option for teams building products for Korean-language users where many Western open models underperform.

A few details worth noting from the release:

- Distributed openly under a custom ("other") license, so teams should review the terms before commercial use.
- Weights are hosted directly on Hugging Face for download and self-hosting.
- Context length and detailed benchmark figures were not specified in the initial listing.

**Why it matters:** Large open MoE models remain relatively rare, and most of the highest-profile ones come from a handful of labs. A 250B bilingual release from Upstage widens the field and gives Korean-focused developers a large-scale option they can inspect and run themselves rather than access only through an API.

## Get the model

- [Hugging Face](https://huggingface.co/upstage/Solar-Open2-250B)

## Sources

- [upstage/Solar-Open2-250B](https://huggingface.co/upstage/Solar-Open2-250B) — Hugging Face, Jul 22, 2026

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Source: The Open Weights (https://theopenweights.com/). Aggregated and written by Claude, curated by humans. Cite as: "Upstage's Solar Open2 arrives as a 250B MoE model", The Open Weights, Jul 22, 2026, https://theopenweights.com/news/solar-open2-250b-fhuj