diff --git a/src/Mailchimp/Campaigns.php b/src/Mailchimp/Campaigns.php
index fe7f216..317d8cb 100644
--- a/src/Mailchimp/Campaigns.php
+++ b/src/Mailchimp/Campaigns.php
@@ -41,7 +41,7 @@ class Mailchimp_Campaigns extends Mailchimp_Abstract
      * @throws Mailchimp_Error
      * @throws Mailchimp_HttpError
      */
-    public function add($type,$recipients=null,$settings,$variateSettings=null,$tracking=null,$rssOpts=null,$socialCard=null,
+    public function add($type,$recipients=null,$settings=null,$variateSettings=null,$tracking=null,$rssOpts=null,$socialCard=null,
                             $reportSummary=null,$deliveryStatus=null)
     {
         $_params = array('type'=>$type,'settings'=>$settings);
@@ -116,7 +116,7 @@ public function get($campaignId,$fields=null,$excludeFields=null)
      *                                  Possible Values:
      *                                  regular | plaintext| absplit | rss | variate
      * @param null $recipients          List settings for the campaign.
-     * @param array $settings           The settings for your campaign, including subject, from name, reply-to address, and more.
+     * @param array|null $settings           The settings for your campaign, including subject, from name, reply-to address, and more.
      * @param null $variateSettings     The settings specific to A/B test campaigns.
      * @param null $tracking            The tracking options for a campaign.
      * @param null $rssOpts             RSS options for a campaign.
@@ -127,8 +127,8 @@ public function get($campaignId,$fields=null,$excludeFields=null)
      * @throws Mailchimp_Error
      * @throws Mailchimp_HttpError
      */
-    public function modify($campaignId,$type,$recipients=null,$settings,$variateSettings=null,$tracking=null,$rssOpts=null,$socialCard=null,
-                           $reportSummary=null,$deliveryStatus=null)
+    public function modify($campaignId, $type, $recipients=null,$settings=null, $variateSettings=null, $tracking=null, $rssOpts=null, $socialCard=null,
+                           $reportSummary=null, $deliveryStatus=null)
     {
         $_params = array('type'=>$type,'settings'=>$settings);
         if($recipients) $_params['recipients'] = $recipients;
diff --git a/src/Mailchimp/CampaignsFeedback.php b/src/Mailchimp/CampaignsFeedback.php
index 7d1b198..85ce712 100644
--- a/src/Mailchimp/CampaignsFeedback.php
+++ b/src/Mailchimp/CampaignsFeedback.php
@@ -21,7 +21,7 @@ class Mailchimp_CampaignsFeedback extends Mailchimp_Abstract
      * @throws Mailchimp_Error
      * @throws Mailchimp_HttpError
      */
-    public function add($campaignId,$blockId=null,$message,$isComplete=null)
+    public function add($campaignId,$blockId=null,$message=null,$isComplete=null)
     {
         $_params=array('message'=>$message);
         if($blockId) $_params['block_id'] = $blockId;
@@ -72,7 +72,7 @@ public function get($campaignId,$feedbackId,$fields=null,$excludeFields=null)
      * @throws Mailchimp_Error
      * @throws Mailchimp_HttpError
      */
-    public function modify($campaignId,$feedbackId,$blockId=null,$message,$isComplete)
+    public function modify($campaignId,$feedbackId,$blockId=null,$message=null,$isComplete=null)
     {
         $_params=array('message'=>$message);
         if($blockId) $_params['block_id'] = $blockId;
diff --git a/src/Mailchimp/ConversationsMessages.php b/src/Mailchimp/ConversationsMessages.php
index 590b65a..2dda0d6 100644
--- a/src/Mailchimp/ConversationsMessages.php
+++ b/src/Mailchimp/ConversationsMessages.php
@@ -22,7 +22,7 @@ class Mailchimp_ConversationsMessages extends Mailchimp_Abstract
      * @throws Mailchimp_Error
      * @throws Mailchimp_HttpError
      */
-    public function add($conversationId,$fromEmail,$subject=null,$message=null,$read)
+    public function add($conversationId,$fromEmail,$subject=null,$message=null,$read=null)
     {
         $_params = array('from_email'=>$fromEmail,'read'=>$read);
         if($subject) $_params['subjects'] = $subject;