Differences between two Software

Hi Dear Sir/ Madam,
In Qiime2 I have seen there is a software named Vsearch. I would like to know differences between Vsearch and Userach?
Are they same?
Thanks a lot

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I would read https://github.com/torognes/vsearch and https://github.com/dereneaton/pyrad/issues/5 to know the differences between Vsearch and Usearch methods. In a nutshell, Vsearch replaces Usearch.