SysInfoTools PST Upgrade and Downgrade - Version 5.0 PST Upgrade and downgrade from SysInfoTools is a powerful PST conversion tool to upgrade or degrade MS Outlook PST files. Using SysIfoTools a user can convert ANSI PST files created using MS Outlook 2000, 2002, xp to Unicode PST Files of MS Outlook 2003 and 2007 similarly it can convert unicode PST file of MS Outlook 2003 and 2007 to ANSI PST file of MS Outlook 2000, 2002, xp. Microsoft Outlook 2000, 2002, XP have overall size limit of 2GB for personal folder, PST files created in these version have ANSI File format and if the size of PST file exceeds then 2GB then PST file gets corrupted. To avoid and overcome this type of situation this tool can be very helpful, to avoid corruption ANSI PST files of earlier version of Microsoft Outlook can be upgraded into UNICODE PST file of Microsoft Outlook 2003 and 2oo7 using this tool. Microsoft Outlook 2003 and Microsoft Outlook 2007 have a larger overall size limit 20 gigabytes (GB) for the personal folders (.pst) file than the .pst files that are in the earlier versions of