The PST files are Outlook personal storage table files. The size of PST file can be increased and decreased through PST upgrade and downgrade tool. The tool increases the PST file size by converting it from ANSI to Unicode PST format. The upgraded PST file can store data upto 20 GB. In the same way the tool can downgrade a PST file by decreasing its size. This can be done by converting Unicode PST file to ANSI PST file format. The PST upgrade and downgrade tool smoothly performs the upgrade and downgrade of PST file.This tool is compatible to all Outlook versions like Outlook 2000, 2003, 2007, 2010, 2013 and 2016( 32 and 64 bit).