cx-newsletter/components/06-plugin_settings.php

<?php

namespace cx_newsletter;
use \exception;

class plugin_settings
extends settings
implements settings_interface {
    protected function get_options() : array {
        return [
            'source_address' => '[email protected]',
            'reply_to_address' => '[email protected]',
            'email_count' => '50',
            'sms_count' => '10',
            'database_version' => 'null',
            'apikey' => 'TEST_APIKEY',
        ];
    }

    public function get_plugin_version() : int {
        return 2;
    }   
}