Use the following links as templates for the versions you want to download. Replace the x & y values with the values of the version you'd like to download; for example:
https://saucelabs.com/downloads/sc-4.6.5-win32.zip
Be sure to check the Sauce Connect changelog for EOLed versions.
Template links:
https://saucelabs.com/downloads/sc-4.x.y-win32.zip
https://saucelabs.com/downloads/sc-4.x.y-macos.zip
https://saucelabs.com/downloads/sc-4.x.y-linux.tar.gz