When will Windows stop asking me to "try the new Outlook"?

There are a few different prompts that get called "try the new Outlook", and each has its own switch, so it helps to know which one you are seeing.

• If it is the toggle at the top right of classic Outlook, you can hide it. In Outlook go to File > Options > General and look for the option to show the Try the new Outlook toggle, and turn it off. If you do not see it, the registry value works too: under HKCU\Software\Microsoft\Office\16.0\Outlook\Options\General create a DWORD named HideNewOutlookToggle and set it to 1, then restart Outlook. IT admins can set the same thing with the Office policy for the new Outlook toggle.
• If it is a popup or banner in Windows or the old Mail app, check Settings > System > Notifications and turn off notifications for the Mail, Outlook or Microsoft Edge app that shows it, and under Settings > Privacy & security > General turn off Show me suggested content in the Settings app and Show me notifications in the Settings app.
• If the old Mail and Calendar app opens the new Outlook, that is because that app has been retired, so the redirect cannot be turned off there. Use classic Outlook or a different mail client instead.
• Close the banner with the X rather than Not now when it offers both, because the X usually lasts longer.

If you tell us whether it shows in Outlook, in Mail, or as a Windows notification, someone can point to the exact setting.