Are you an MAPI developer? Then, this article is targetted for you. The API elements (like, IXPLogon::RegisterOptions, OPTIONDATA, OPTIONCALLBACK, IMAPISession::MessageOptions, IMAPISession::QueryDefaultMessageOpt, IAddrBook::RecipOptions, IAddrBook::QueryDefaultRecipOpt)  are deprecated in Microsoft Outlook 2013. They are no longer supported and you should not use them in new projects. These API elements are deprecated in this release because of obsolete message and recipient options. For more information, you can refer the related article.