Outlook 2010 is the latest version of Outlook while, Outlook XP is one of the earlier versions of Outlook. ANSI and Unicode are the two application formats of Outlook, Earlier versions of Outlook (2000, 2002 and 97) has ANSI application format and Newer versions of Outlook has Unicode application format. The database files created in Outlook are called PST files so, the database files of Earlier Outlook versions are called ANSI PST and the database files of Newer Outlook versions are called Unicode PST. ANSI PST can grow upto 2 GB only and Unicode PST can grow upto 20 GB.
So, if you are using Outlook XP and you want to convert Outlook XP to Outlook 2010 for experiencing better performance, high speed, better graphics, extended size limit of Outlook 2010 then, PST Upgrade software is one impeccable mode for you.
PST Upgrade software is one fully loaded solution to upgrade from Outlook XP to Outlook 2003, 2007 and 2010 because it provides simplicity in the conversion process and it maintains all the things, which are necessary in qualitative upgradation.