It's been years since I haven't seen, or heard of, any email client which wouldn't be capable of reading, and displaying, HTML.
I'm in the process of creating email templates for a new website, and wondering if it's worth the effort to try to provide a text version of every automated email sent.
To put things simply, is there still any good reason to send a text version along with HTML emails?
A text version will definitely reduce the likelihood of your message ending up in spam, and will be friendlier to user agents that can't or won't display HTML. A text version can be generated automatically from the HTML by most email libraries.
Why purposefully alienate some users when the alternative doesn't cost any more work?