Change feed / 2026-07-31
DeepSeek V4 Flash retrained and swapped into the live alias in place
DeepSeek replaced the deepseek-v4-flash alias with a retrained build (0731) — 'the calling method remains unchanged' per their own release note — with drastically different agentic behavior (it now beats V4 Pro on all nine agent benchmarks). The dated open weights were published separately; API users were switched without action. The largest-share model on OpenRouter is also the clearest current example of the silent-swap failure mode.
Evidencequoted verbatim from the source
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Plain
ModelRiskIndex. "DeepSeek V4 Flash retrained and swapped into the live alias in place." Change feed, 2026-07-31. https://modelriskindex.com/changes/deepseek-v4-flash-silent-swap
BibTeX
@misc{mri-2026-07-31,
title = {DeepSeek V4 Flash retrained and swapped into the live alias in place},
author = {{ModelRiskIndex}},
year = {2026},
note = {Change feed, 2026-07-31},
url = {https://modelriskindex.com/changes/deepseek-v4-flash-silent-swap}
}Please cite the dated entry rather than the site root. Every assessment here is a point-in-time judgment bound to evidence retrieved on a specific date — an undated citation asserts something the data does not.
