dotnet SmtpClient should not be used

I am very late to the party, but today I learned that the good old dotnet SmptClient is considered obsolete and should not be used. Quoting the documentation: We don’t recommend using the SmtpClient class for new development because SmtpClient doesn’t support many modern protocols. Use MailKit or other libraries instead. (source) Interestingly, Microsoft is recommending a third-party open-source library as an alternative. I hope we’ll see more of that in the future. »