Hello I used DESeq2 on RStudio version 3.2.3 about 3 years ago How can I found out which version of DESeq2 was used?

Thanks

RStudio makes no difference, DESeq2 is based on R version.

You can look up specific releases of Bioconductor by changing the URL:

https://bioconductor.org/packages/3.0/bioc/html/DESeq2.html

https://bioconductor.org/packages/3.1/bioc/html/DESeq2.html

These two were for R 3.1.2 and 3.2.2 respectively.