2007 you should be fine…. anything before you might have issues.
REGISTER or login:
will easily read outlook 2007 PST file in Outlook 2010 without any difficulty
because both Outlook editions support the same PST file format (Unicode). Now to import outlook 2007 PST file in outlook
2010 by the using import option.
the Outlook >> File >> Import and Export >> Import from
another program or file >> Next >> Personal Folder File (.pst)
>> Next >> Browse.
then locate and select outlook 2007 PST file and proceed then select the folder
where you to import. It will be imported into your personal folder.