# T5v1.1 tokenizer legacy=False

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**Category:** 🤗Tokenizers\
**Created:** [February 22, 2024, 3:36am UTC](/static-proxy?url=https%3A%2F%2Fdiscuss.huggingface.co%2Ft%2Ft5v1-1-tokenizer-legacy-false%2F74250 "2024-02-22T03:36:16Z")\
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**Author:** ![Nevermetyou](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/nevermetyou/32/21618_2.png) [@Nevermetyou](/static-proxy?url=https%3A%2F%2Fdiscuss.huggingface.co%2Fu%2FNevermetyou)%5C
**Post date:** [February 22, 2024, 3:36am UTC](/static-proxy?url=https%3A%2F%2Fdiscuss.huggingface.co%2Ft%2Ft5v1-1-tokenizer-legacy-false%2F74250%2F1 "2024-02-22T03:36:16Z")

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Hello, I am using t5v1.1 right now and have a question about the arg `legacy`. The only thing I know is it involves fixing some bugs.

> - **legacy** (`bool`, _optional_) — Whether or not the `legacy` behaviour of the tokenizer should be used. Legacy is before the merge of #24622 and #25224 which includes fixes to properly handle tokens that appear after special tokens. A simple example:
> - `legacy=True`:

But should I set it to false to use new behavior??