Errors Inbox in New Relic's main navigation is now Triage Inbox (Errors Inbox). Open it and you'll find the same two places you already use: Errors Inbox and Performance Risks Inbox.
This is a change to the label for the main navigation entry and nothing else. There's no new page and no new feature to turn on. Errors Inbox and Performance Risks Inbox both work exactly as they did before, Errors Inbox inside your entity views is unchanged, and there's no change to pricing or billing.
We're keeping (Errors Inbox) next to the new name Triage Inbox for a few more months so the entry stays easy to recognize.