I have added this line to wp-config.php as per your documentation in order to increase the number of Lists available from 20 to 30.
define('NEWSLETTER_LIST_MAX', 30);
After doing that modifications, I immediately went to the diagnostic panel and forced an upgrade.
however, even after loggin in and out, I still only see 20 lists available.
Can you telel me what additional steps might be required to make these additional lists (or preferences) available?
Thank you. – David