Does anyone know what mail protocol the “New Outlook.com” uses and what other email clients support that protocol other than Office Outlook?

Original Title: The New Outlook.com

The latest communications bomb for Windows Live Mail 2012 users states the following:

"Anyone who currently uses Windows Live Mail 2012 to connect to Outlook.com needs to switch to an alternate email application..."

Does anyone know what mail protocol the "New Outlook.com" uses and what other email clients support that protocol other than Office Outlook?  Obviously it is not POP or IMAP, as stated in their communique.

FYI, I am using Windows 10 and I have a lot of Storage Folders in WLM 2012.  I do not want to move them to the web and apparently the Mail app doesn't support Storage Folders.  I have 2 @msn.com accounts with server setup as follows:

"My mail server is an HTTP server"

Server URL:  https://mail.services.live.com/DeltaSync_v2.0.0/sync.aspxemail

Any assistance is greatly appreciated.