Kernel for PST Compress & Compact supports various versions of MS Outlook including 2002, 2003, and 2007. The tool is compatible with various Windows operating systems including 9x, NT, 2000, XP, 2003, Vista, 7, 8 and 8.1. To compress Outlook PST files, the tool needs basic system requirement - Pentium Class processor, 256 MB RAM and 7MB free disk space for tool installation.