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DeepSeek Upgrades V4.1 Flash With Big Agent Gains and No Price Change

DeepSeek's V4.1-Flash-1017 update posts big jumps on coding and agent benchmarks, runs tasks faster, keeps the same API price, and ships open weights under the MIT license.

By Gobi Daily2 min readFact-checked

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DeepSeek has upgraded its smallest current model. On October 17, 2026, the company’s API changelog announced DeepSeek-V4.1-Flash-1017, an update to the V4.1 Flash model it released on September 10. The new version is already serving DeepSeek’s web and app chat as well as the API, where developers keep calling it as deepseek-flash. DeepSeek says the calling method and pricing are unchanged.

What improved

DeepSeek calls this a minor update, but its own benchmark numbers show sizable jumps over the previous V4.1 Flash:

  • Terminal-Bench 4.0: 42.3, up from 31.2
  • DeepSWE v1.1: 77.0, up from 74.2
  • ProgramBench: 29.1, up from 20.3
  • Automation-Bench v1.0.6: 60.5, up from 54.8
  • Agents’ Last Exam: 35.4, up from 31.8
  • Apex Bench v1.1: 72.1, up from 64.6
  • Humanity’s Last Exam (no tools): 42.6, up from 36.8

DeepSeek says it ran Terminal-Bench 4.0 in the Claude Code harness and DeepSWE in the Mini-SWE-V2 harness.

How it compares

The model card on Hugging Face lines the new Flash up against other models. On Terminal-Bench 4.0, DeepSeek lists GPT-5.6 Sol at 39.9 and Claude Opus 5 at 51.8, so the new Flash lands between them. On DeepSWE v1.1 it lists the new Flash ahead of both, at 77.0 against 74.0 for Opus 5 and 73.0 for GPT-5.6 Sol. On Humanity’s Last Exam without tools, Opus 5 stays well ahead at 56.3.

DeepSeek also says the update cuts task run time and output length, so the same jobs finish faster and cost less. It specifically tuned the model for its own DeepSeek Harness and for Tencent’s CodeBuddy and WorkBuddy, and recommends DeepSeek Harness 0.2.1-rc.1 or later.

Open weights

The weights are on Hugging Face under the MIT license. The listing shows about 763 billion parameters, and DeepSeek recommends a 1 million token context window with outputs of at least 256K tokens.

A search API, too

In the same changelog entry, DeepSeek said it is opening up its in-house search engine to developers. It says DeepSeek Search handles hundreds of millions of search requests a day, indexes hundreds of billions of web pages, and filters out SEO spam and low-quality AI-generated content.

The caveat

Every number here comes from DeepSeek itself. Independent testing will show whether the gains hold up outside the company’s own harnesses.

Sources

  1. Change LogDeepSeek API Docs
  2. DeepSeek-V4.1-Flash-1017 model cardHugging Face

Fact-checked against the primary sources above on Oct 17, 2026. Spot an error?Request a correction.

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