diff --git a/lib/recurly/currency_list.php b/lib/recurly/currency_list.php
index 246af95d..f54a7d68 100644
--- a/lib/recurly/currency_list.php
+++ b/lib/recurly/currency_list.php
@@ -20,35 +20,35 @@ public function getCurrency($currencyCode) {
     return isset($this->currencies[$currencyCode]) ? $this->currencies[$currencyCode] : null;
   }
 
-  public function offsetSet($offset, $value) {
-    return $this->addCurrency($offset, $value);
+  public function offsetSet($offset, $value): void {
+    $this->addCurrency($offset, $value);
   }
 
-  public function offsetExists($offset) {
+  public function offsetExists($offset): bool {
     return isset($this->currencies[$offset]);
   }
 
-  public function offsetUnset($offset) {
+  public function offsetUnset($offset): void {
     unset($this->currencies[$offset]);
   }
 
-  public function offsetGet($offset) {
+  public function offsetGet($offset): mixed {
     return $this->getCurrency($offset);
   }
 
   public function __set($k, $v) {
-    return $this->offsetSet($k, $v);
+    $this->offsetSet($k, $v);
   }
 
   public function __get($k) {
     return $this->offsetGet($k);
   }
 
-  public function count() {
+  public function count(): int {
     return count($this->currencies);
   }
 
-  public function getIterator() {
+  public function getIterator(): Traversable {
     return new ArrayIterator($this->currencies);
   }
 
diff --git a/lib/recurly/custom_field_list.php b/lib/recurly/custom_field_list.php
index 9604d5a7..38944845 100644
--- a/lib/recurly/custom_field_list.php
+++ b/lib/recurly/custom_field_list.php
@@ -10,7 +10,7 @@ class Recurly_CustomFieldList extends ArrayObject
    * @param object $value Must be instance of Recurly_CustomField
    * @throws Exception
    */
-  public function offsetSet($index, $value) {
+  public function offsetSet($index, $value): void {
     if (!$value instanceof Recurly_CustomField) {
       throw new Exception("value must be an instance of Recurly_CustomField");
     }
@@ -25,7 +25,7 @@ public function offsetSet($index, $value) {
     parent::offsetSet($index, $value);
   }
 
-  public function offsetUnset($index) {
+  public function offsetUnset($index): void {
     parent::offsetSet($index, new Recurly_CustomField($index, null));
   }
 
diff --git a/lib/recurly/error_list.php b/lib/recurly/error_list.php
index 8b49822d..f4b3169c 100644
--- a/lib/recurly/error_list.php
+++ b/lib/recurly/error_list.php
@@ -25,29 +25,29 @@ function __construct() {
   }
 
   // array access to the errors collection
-  public function offsetSet($offset, $value) {
+  public function offsetSet($offset, $value): void {
     if (is_null($offset)) {
       $this->errors[] = $value;
     } else {
       $this->errors[$offset] = $value;
     }
   }
-  public function offsetExists($offset) {
+  public function offsetExists($offset): bool {
     return isset($this->errors[$offset]);
   }
-  public function offsetUnset($offset) {
+  public function offsetUnset($offset): void {
     unset($this->errors[$offset]);
   }
-  public function offsetGet($offset) {
+  public function offsetGet($offset): mixed {
     return isset($this->errors[$offset]) ? $this->errors[$offset] : null;
   }
 
-  public function count()
+  public function count(): int
   {
     return count($this->errors);
   }
 
-  public function getIterator() {
+  public function getIterator(): Traversable {
     return new ArrayIterator($this->errors);
   }
 
diff --git a/lib/recurly/pager.php b/lib/recurly/pager.php
index 8201be59..dffb19f4 100644
--- a/lib/recurly/pager.php
+++ b/lib/recurly/pager.php
@@ -18,7 +18,7 @@ abstract class Recurly_Pager extends Recurly_Base implements Iterator, Countable
    * @return integer number of records in list
    * @throws Recurly_Error
    */
-  public function count() {
+  public function count(): int {
     if (isset($this->_href)) {
       $headers = Recurly_Base::_head($this->_href, $this->_client);
       if (isset($headers['x-records'])) {
@@ -28,7 +28,7 @@ public function count() {
       return count($this->_objects);
     }
 
-    return null;
+    return 0;
   }
 
   protected function get_first_page() {
@@ -47,7 +47,7 @@ protected function get_first_page() {
    *
    * @throws Recurly_Error
    */
-  public function rewind() {
+  public function rewind(): void {
     $this->_loadFrom($this->_href);
     $this->_position = 0;
   }
@@ -58,7 +58,7 @@ public function rewind() {
    * @return Recurly_Resource the current object
    * @throws Recurly_Error
    */
-  public function current()
+  public function current(): mixed
   {
     // Work around pre-PHP 5.5 issue that prevents `empty($this->count())`:
     if (!isset($this->_objects)) {
@@ -84,21 +84,21 @@ public function current()
   /**
    * @return integer current position within the current page
    */
-  public function key() {
+  public function key(): mixed {
     return $this->_position;
   }
 
   /**
    * Increments the position to the next element
    */
-  public function next() {
+  public function next(): void {
     ++$this->_position;
   }
 
   /**
    * @return boolean True if the current position is valid.
    */
-  public function valid() {
+  public function valid(): bool {
     return (isset($this->_objects[$this->_position]) || isset($this->_links['next']));
   }