Don't deprecate Search-Mailbox in EXO
"Note : In cloud-based environments, the Search-Mailbox cmdlet is being deprecated in favor of New-ComplianceSearch"
Replacing the capability of Search-Mailbox with the new ComplianceSearch and ComplianceSearchActions cmds is a terrible user experience and moves a single step process to a multi-step process with manual intervention. If this functionality is to go away for good, this will severely hinder our ability to execute requests in a timely and efficient manner.
I would argue that these are different use cases and can easily co-exist in the tenant.
O365 is supposed to be in the business of streamlining processes with efficiency, not convoluting them unnecessarily.
according to article
we can't use -Purge switch to cleanup whole mailbox on acceptable way and time.
A maximum of 10 items per mailbox can be removed at one time. Because the capability to search for and remove messages is intended to be an incident-response tool, this limit helps ensure that messages are quickly removed from mailboxes. This action isn't intended to clean up user mailboxes.
The compliance search fulfills a function for case management and legal. In my opinion, this is not a replacement for search-mailbox. Search-mailbox can be used to move email directly from one mailbox to another while keeping an existing folder structure in a one-liner. Attempting to perform the same thing with the compliance search and .PST export is a much slower and manual process.