I would like to suggest a certified solution like Zimbra to Office 365 Converter Software. This application transfer Zimbra items like e-mail, contacts, journal, notes, and so on. This application transfer Zimbra to Office 365 and a variety of file formats including PST, EML, MSG, EMLX, vCard, vCal, etc.
Read more: https://www.kdetools.com/zimbra/office-365.html