# Anthropic's watermark rollout leaves a loophole on two older Claude models

**Published:** October 31, 2026
**Author:** Matthias Bastian
**Source:** The Decoder
**Language:** en-US
**HTML:** https://aiqazaqstan.com/en/articles/anthropic-s-watermark-rollout-leaves-a-loophole-on-two-older-claude-mode

Anthropic is expanding its text watermark to four more Claude models to meet the EU AI Act's December deadline. On the older models Claude Opus 4.6 and Sonnet 4.6, developers can bypass the watermark by tweaking a single sampling parameter. Anthropic addresses the loophole with…

> From the original source: **The Decoder**
> [Read full article at The Decoder](https://the-decoder.com/anthropics-watermark-rollout-leaves-a-loophole-on-two-older-claude-models/)

**Tags:** #Anthropic

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