You can try commercial solution like KDETools Zimbra to Office 365 Converter Tool is the most powerful tool for migrating Zimbra to Office 365. Some additional features are:

• Zimbra to Office 365 converter convert Zimbra TGZ file to Office 365 other file formats like PST, OLM, NSF, MBOX, PDF, EML, EMLX, HTML, etc.
• This tool has Fast conversion of data without losing any data.
• Corrupted file also transformed securely.
• This tool works on all versions of Windows, including 7, 8, 8.1, XP, and 10.
Read More: https://www.kdetools.com/zimbra/office-365.html