Using KDETools Zimbra to Office 365 is a good way to convert Zimbra files to Office 365. Besides converting Zimbra files to Office 365 accounts, it can also convert other file formats such as PST, EML, EMLX, HTML, and PDF. The conversion is done without any changes being made to the source files.
Read more:
https://www.kdetools.com/zimbra/office-365.html