It’s a good idea to replace older calls to the Get-Mailbox cmdlet with Get-ExoMailbox. However, it’s not just a matter of cut and paste updates. In some cases, the nature of the new REST-based cmdlets mean that some additional care is necessary to ensure that the updated code works as expected. As we examine in this article, filters are just one example where some attention to detail is needed to make sure Exchange Online delivers the right set of mailbox data.
https://practical365.com/using-filters-with-the-get-exomailbox-cmdlet/
