DeepSeek V4.1 Flash weights out: 552B multimodal, 1M context, SGLang day-0 support

zhaoran_wang · x · 2026-09-11

SGLang announced day-0 inference and RL support for DeepSeek V4.1 Flash, whose weights are now out. V4.1 extends the V4 stack with compressed KV shared across layers, a two-stage sparse indexer, and a 196B Engram lookup memory.

It's natively multimodal with a 552B backbone (16B active decode, 8B prefill) and supports up to 1M context, with 'very exciting performance upgrades' teased for the coming days. The retweet notes Chinese open-source release cycles have shrunk from yearly to monthly.

Related event: DeepSeek releases V4.1-Flash: 552B MoE beats flagships at low cost(56 posts)→

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