We recently updated our store to 1.5 for 1.3.9h and first thing we noticed after making the site live was that it no longer sends html e-mails.

I've checked the following:
(config->e-mail options)
- Use MIME HTML When Sending Emails = true
- Send E-Mails = true
- I've tried to send e-mails both from the admin (tools -> send email) and from the store, but it only shows up as text either way.
- In the e-mail_archive table in the database, nothing is written to the e-mail_html field.