New Outlook vs. Outlook in Microsoft 365

IF "New Outlook" Is Replacing the free Windows Mail App. Then Why Does my Paid outlook have a radio button to switch to "New Outlook" Is this a different "New Outlooks" and why would MS push people away from an app they are paying for in lieu of a free app that lacks features present in the paid one. This has to be branding in the most confusing way possible and I want to know is there 2 separate New Outlooks or no, and if no can we remove the radio button to switch since this is creating support nightmares already. Thank you.

my thoughts exactly...

I am a paid subscriber to Office 365 and feel like I had the more robust app in Outlook for 365 but am seeing the button to switch to New Outlook... what does that mean???

Microsoft - very confusing maybe you could call /name these products something differently...

If you like classic, ignore the try new Outlook switch - or set a reg key to hide it.

The key you need to set is at Use Classic Outlook, not New Outlook - if you don't want to edit the registry, there are instructions to set it with opening the registry editor and a .reg file.

I tried the non-Registry adjustment (D-word change), to be on the safe side. The Command Line informed me the procedure had been successfully completed:

But the invitation remains there (Top-right). Why? Do I have to close Outlook 365 (Paid)/Classic and it will then vanish? (Further comment added).

Answer: Yes, it did (delight). Thank you, Diane.

I am now curious about one thing. Like many, I am always highly cautious about adjusting the Registry and understand that backing up avoids catastrophe. Since in this case the alteration was conducted without applying your first Reg-change/Regedit solution, does this 'hack' apply to other/more Registry changes? In short, is it safer than the conventional Regedit backup-and-save method, as the worst that can happen is a mis-type, as I found when I initially omitted 'reg add', being unsure it was part of the intended Path?

First - for many Outlook registry keys, you need to restart Outlook for it to take effect. When the key path includes Policies or HKLM (local machine) restarting Outlook is required. Keys in the regular office path are maybe/maybe not as to whether restarting Outlook is needed. Sometimes you just need to switch between calendar and mail a couple of times to trigger it.

But because this specific key changes the interface, restarting is required.

Whether you need to back up the registry depends on the keys you are touching. Adding Outlook (or any office-related) key, the worst it will do is cause the app not to work - windows will boot and you can delete the key you added. If you are deleting or changing a value, then you might want to back it up, unless the value is being switched from 0 to 1 or something easy to remember. (When I'm deleting keys, I often just rename it - with a dash at the beginning or end of the name - the software won't use it, and I can change the name back if needed.)

Many thanks for taking the trouble to provide a full explanation, Diane.