DeepSeek-V3.1-Terminus

DeepSeek-V3.1-Terminus was released September 22, 2025 as a refined iteration of DeepSeek-V3.1 (August 2025), built directly from user feedback. Rather than changing the architecture, Terminus targets reliability: it eliminates the Chinese-English language mixing and spurious character insertions that plagued V3.1, and delivers more consistent outputs across benchmarks.

It also upgrades DeepSeek's built-in Code Agent and Search Agent, improving accuracy in programming tasks and web information retrieval. Launched simultaneously across the DeepSeek app, web, and API, it became the production-recommended checkpoint of the V3.1 generation, with weights available on Hugging Face. The "Terminus" name signals a mature, production-hardened endpoint rather than an intermediate release.