Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Just to verify, you mentioned Classic Outlook on Mac, do you mean Legacy Outlook for Mac?
If yes, when you install New Outlook for Mac, in your New Outlook for Mac, you can go to Outlook > select Legacy Outlook to revert back.
If you do not have New Outlook on your Mac, install it via Update history for Office for Mac - Office release notes | Microsoft Learn
In case you do not see the Legacy Outlook option, make sure your license does support it:
If you are referring to Classic Outlook for Windows, unfortunately, Classic Outlook is designed specifically to work on Windows OS. Therefore, you cannot install it on MacOS.
I hope this information helps, if you need anything else, please feel free to reach out.
I look forward for your reply.
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