Suppose a website provides the facility to compose and send monthly email newsletters to subscribers. The email content is essentially html.
What are the implications of migrating the content to html5? In particular, how would most non-compliant email viewers handle the html5shiv script, if either:
Alternatively, should html5 not yet be used as an emailable format?
No, html5shiv is not viable in email. html5shiv is JavaScript. JavaScript is not viable in HTML formatted email.
I'm not aware of any email client that allows JavaScript to execute (other than through (already patched) security holes).