The information below is meant to provide an "easy" means of locating and downloading the code/binaries you need to run Primer3. As such, we have provided links to help you reach the most recent versions of the software. ALL downloads including older versions of the software are available from the GitHub Releases Page.
Primer3 (the C code)
Release 2.4.0 (November 03, 2017)
Release 4.1.0 (November 04, 2017)
Release 2.5.0 (November 04, 2017)