You can use Advance software like KDETools Zimbra to Exchange Server Converter tool.

Some main features are:

This application is quickly import Zimbra file to Exchange Server without facing any hassle.

This application also simply import Zimbra file to Gmail, Office 365 and etc without any hassle.

This software also import Zimbra files to Exchange server and other file formats such as PST, MBOX, NSF, EML, EMLX, PDF, HTML, etc.

This application shows free preview of the data before the conversion process.

Read More: https://www.kdetools.com/zimbra/exchange/