PADS 9.4.1 is a full standalone release, not a patch or an update. However, it can be installed in your existing 9.4 target directory and will update all the necessary files to bring your 9.4 tree up to 9.4.1. Please see the Do I need to remove PADS 9.4 before installing PADS 9.4.1? doc for infomation on 9.4.1 install scenarios.