I would like to recommend you secure application Zimbra to Office 365 Converter Tool to import Zimbra file to Office 365 account. Various features are:
• It is the secure and protected tool that can capably import Zimbra file to Office 365 and other file formats like PST, MBOX, EML, EMLX, HTML, PDF, etc.
• Corrupted file also transformed firmly and Meta properties email get move.
• This application is also supports all version of MS Outlook & Windows.
Read more: https://www.kdetools.com/zimbra/office-365.html