There some usefully info here, but unfortunately the url layout does not work anymore.
WHAT DOES NOT WORK
https://outlook.live.com/owa/#ItemID=<ItemID>
https://outlook.live.com/owa/#ItemID=<ItemID>&exvsurl=1
https://outlook.live.com/owa/#ItemID=<ItemID>&exvsurl=1&viewmodel=ReadMessageItem
https://outlook.live.com/owa/?ItemID=<ItemID>
https://outlook.live.com/owa/?ItemID=<ItemID>&exvsurl=1
WHAT WORKS
https://outlook.live.com/owa/?ItemID=<ItemID>&exvsurl=1&viewmodel=ReadMessageItem
https://outlook.live.com/mail/0/deeplink?ItemID=<ItemID>&exvsurl=1&viewmodel=ReadMessageItem
https://outlook.live.com/mail/0/deeplink?ItemID=<ItemID>&exvsurl=1
https://outlook.live.com/mail/0/deeplink?ItemID=<ItemID>
Note: mind the %3D%3D
at the end of the ItemID
, it must not be forgiven!
Automating
Add a bookmark with this as the url:
javascript:id=document.URL.split("/id/")%5B1%5D.split(encodeURIComponent("=="))%5B0%5D+encodeURIComponent("==");u=`https://outlook.live.com/mail/0/deeplink?ItemID=${id}`;window.open(u)
or
javascript:id=document.URL.split("/id/")%5B1%5D.split(encodeURIComponent("=="))%5B0%5D+encodeURIComponent("==");u=`https://outlook.live.com/owa/?ItemID=${id}&exvsurl=1&viewmodel=ReadMessageItem`;window.open(u)
Now, open the email normally from OWA, then click the bookmarklet, it will open the email in a new tab from its deeplink.
Note: untested with other browsers than Chrome Desktop.