ullNewsletter enable double-opt-in
apps/frontend/config/app.yml:
all: ull_newsletter: enable_double_opt_in: true
If you want to modify the email, you can do so by overriding BaseUllNewsletterActions::sendDoubleOptInMail() in your custom action at apps/frontend/modules/ullNewsletter/actions/actions.class.php.
How it works
A visitor enters his email address at ullNewletter/public. The desired mailinglist subscriptions are saved normally as without double-opt-in.
We still have to ensure, that the user gets no emails unless he has confirmed his subscription via the double opt in email.
We achive that by setting UllUser->newsletter_consent_no_at to NOW() (= no spooled mass emails) and unset it when the user confirms via the double opt in email.