Did SQL Server ever add user principal name support?

I ran into an issue today where the User Principal Name was greater than 20 characters in length, so the samAccountName was capped at 20. This resulted in SQL Server not finding the user when the UPN was typed in, even in Domain\Username format. Googling has led me to several pages from 2014 or older, and even a Q&A on this forum. A detailed explanation may have been on Microsoft Connect, but it's retired and no longer available Can someone confirm that even SQL Server 2016 and beyond (or Azure) still only support samAccountNames?