Today I added a way to insert custom html and text to digest/summary emails. In the past, only the colour scheme could be customized. Now you can insert arbitrary html using the existing Admin > Customize > Text Content interface and searching for “digest.custom”. Narrow it down to the html emails with “digest.custom.html”.
header field will replace the default header, which is currently your site’s logo on the left side.
The rest of the fields can be used to insert banner ads, special offers, additional unsubscribe instructions, important announcements, and anything else that should be targeted at users who haven’t been on your site for a while.