If you are searching for useful tool to transfer Zimbra file to Office 365, then you can use Zimbra to Office 365 Converter.

Some features are:

This application also transfers Zimbra contacts and calendar to Office 365 file format.

Convert Zimbra to numerous file formats for example PST, EML, EMLX, HTML, OLM, NSF, MBOX, and etc.

Supports all versions of MS Outlook & Windows.

Read more: https://www.kdetools.com/zimbra/office-365.html