I beg your pardon, but what exactly are you asking here? If an Outlook user says "Unicode", it means either she/he is talking about the PST file format or the Unicode characters. Are you telling this, "I can't see some of the characters since they are Unicode"? Or this, "the emails are stored in a Unicode PST file"? Look dear, Outlook 2003 and later versions including the latest 2016, use Unicode file format. If you were previously using Outlook 2013, it makes no difference since both support Unicode format.
Your question is DAMN confusing. Help us please, so that we help you.