In my testing I was only able to get digests to mail from my web server when the email package size was 0. I assumed this was something about how my web server email interface was configured, which I can’t control.
I also assumed that when
$html_messenger->send() was called it placed it into the queue unless
email_package_size = 0. It’s counter-intuitive to call
$html_messenger->send() and then have to call
$html_messenger->save_queue() afterward to ensure it gets in the queue. Thanks to Petr, he determined this was the way it is apparently done.
So if you are using digests, after you install this release feel free to change your email package size from 0.