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Kimi K2.5 Bids Farewell: Moonshot AI's First Trillion-Parameter Model Retires

Moonshot AI has officially announced that Kimi K2.5, its first trillion-parameter multimodal model, will be retired at the end of this month. The news came via Kimi's official Weibo account, marking the end of an era for a model that has been a cornerstone of the company's AI offerings since its launch and open-sourcing in January this year.

K2.5 was not just any model; it was the most versatile in Kimi's history. With a native multimodal architecture, it could handle both visual and text inputs, switch between thinking and non-thinking modes, and tackle everything from casual dialogue to complex Agent tasks. It achieved state-of-the-art performance among open-source models on tasks like Agents, code, images, videos, and general intelligence, making it a go-to choice for developers and researchers alike.

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But all good things must come to an end. The retirement of K2.5 signals a strategic shift for Moonshot AI, which is now fully focusing on its successor, Kimi K3. Open-sourced in July, K3 is a behemoth with 2.8 trillion parameters, built using the KDA hybrid linear attention mechanism and attention residual technology. It natively supports visual understanding and boasts a context window of up to 1 million tokens—enough to process entire books in a single pass.

The official statement highlighted that K3 is the first open-source model to reach the 2.8 trillion parameter scale. For the past 12 months, Kimi has held the record for the largest open-source model scale for 9 of those months, a testament to Moonshot AI's commitment to pushing the boundaries of what's possible in open-source AI.

As K2.5 rides off into the sunset, the torch has been passed. K3 is now the flagship, and with its massive scale and advanced capabilities, it's poised to continue Kimi's legacy of innovation. For developers and AI enthusiasts, this transition is both bittersweet and exciting—a farewell to a trusted tool, and a welcome to a new era of possibilities.

Key Points

  • Kimi K2.5, Moonshot AI's first trillion-parameter multimodal model, retires at the end of this month.
  • K2.5 was open-sourced in January and excelled in Agents, code, images, videos, and general intelligence.
  • Its successor, Kimi K3, open-sourced in July, features 2.8 trillion parameters and a 1-million-token context window.
  • Moonshot AI has held the record for the largest open-source model scale for 9 of the past 12 months.