Focused Inbox will replace Clutter. After switching, you'll no longer receive less-important email in the Clutter folder. Instead, email will be split between the Focused and Other tabs in your inbox.

Does clutter still exist in Outlook?

On January 31, 2020, there won't be any more clutter in Outlook. Oh, you'll still get just as many unimportant messages as before, but they won't be sorted into a Clutter folder. Instead, you'll use Microsoft's replacement, Focused Inbox, to read “Focused” and “Other” messages.

What happened Outlook clutter?

Focused Inbox—which you can toggle on and off using a switch in the View tab—just changes your Inbox to show “Focused” and “Other” tabs. Microsoft has now confirmed that Clutter will be gone by January 31st, 2020, leaving users with just Focused Inbox.