Basic Authentication and Exchange Online – February 2021 Update

JeremyTBradshaw thank you for responding, that was the answer I was hoping for. Good to hear that I can still use the EWS API for awhile (hopefully years) as I tried to implement Microsoft Graph authentication in my Outlook add-in on desktop via MSAL, but the user experience wasn't great with all the Dialog boxes constantly popping up. I couldn't use SSO authentication either as my API is on a different domain to my web. I've also read on the Office-js github page there is a few issues with Office.context.auth.getAccessTokenAsync.