Subscribe By Email throws fatal error


We've been using WordPress Multi-site for a while, and we keep on encountering one specific error that we can't seem to understand how it came to be.

The Subscribe By Email plugin is installed in all the network, but not activated by default. A lot of blog administrators on the network activate it without issue. But a lot of administrators find themselves greeted by a blank screen after activating it.

Every single time a user contacts us about a blank screen on their WP blog, once I deactivate the Subscribe By Email plugin in the database, the blog works fine again.

Here's the error it is throwing :

[15-Sep-2015 10:12:34] PHP Fatal error: Call to undefined method Incsub_Subscribe_By_Email_Model::get_email_list() in /space/www/ on line 115

Indeed, when I look at the files of the plugin (downloaded directly from your website today (v 3.4.3), you can see that in function upgrade_247b() there is a $this->get_email_list() that does not match any function (neither in the plugin itself nor in wordpress core).

public function upgrade_247b() {
        global $wpdb;

        $results = $wpdb->get_results( "SELECT * FROM $this->subscriptions_log_table WHERE mail_settings != '' AND ( mails_list = '' OR mails_list IS NULL )");

        $emails_list = $this->get_email_list();
        foreach ( $emails_list as $key => $email_details ) {
            $emails_list[ $key ]['status'] = false;
        foreach ( $results as $result ) {
            $new_emails_list = $emails_list;
            foreach ( $emails_list as $key => $email ) {
                $last_id = $key;
                if ( absint( $result->mail_recipients ) == absint( $key ) ) {
                else {
                    $new_emails_list[ $key ]['status'] = true;
            $this->update_log_emails_list( $result->id, $new_emails_list );
        unset( $new_email_list );
        unset( $emails_list );

However, what I found out, is that in some older version of your plugin (v from 2014/07/08), this same function would call $this->get_email_list()
successfully on line 174, and the function get_email_list() exists in line 224.

Can we have a patch for this ? Right now, your platform is sending out broken builds to everyone.