…ils with header "Content-Type: multipart/alternative", if boundary token is not enclosed by quotes. As a result, HTML emails sent using Nodemailer will not be displayed on "Yahoo! Web Mail", if following change will not be applied.
…ys restart with an EHLO after TLS connection start
…as base64 does not need to be on a single wrapped line
…ed multiple times and would generate multiple MAIL FROM: commands