diff --git a/CHANGELOG.md b/CHANGELOG.md
index c63179b..5f739b6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,12 +1,14 @@
 # Release Notes for KlaviyoConnect
 
+## 4.0.11 - 2022-06-29
+### Fixed
 
-## 5.0.0 - 2022-06-15
-
-- Separate Craft 4 version
+- Fixed issue with use of mixed return types on PHP 7.x
+- Fixed deprecated use of parseEnv()
+- Fixed formatting of this changelog
 
 ## 4.0.10 - 2022-06-13
-## Added
+### Added
 
 - Added a service method to retrieve a Klaviyo Person ID using an email address
 - Added a service method to update a Klaviyo profile 
@@ -14,7 +16,7 @@
 
 ## 4.0.9 - 2022-06-07
 
-## Fixed
+### Fixed
 
 - Fixes issue in Lists field type where list selection isn't saved, or previous setting is nulled, if the entry is first saved by an automatic draft.
 
diff --git a/src/controllers/ApiController.php b/src/controllers/ApiController.php
index 7b4c3ec..a16ac38 100644
--- a/src/controllers/ApiController.php
+++ b/src/controllers/ApiController.php
@@ -29,7 +29,7 @@ class ApiController extends Controller
      * @access	public
      * @return	void
      */
-    public function actionTrack()
+    public function actionTrack() // no return type as mixed is PHP 8 only
     {
         $this->requirePostRequest();
 
@@ -282,7 +282,7 @@ private function identify(): void
      * @access	private
      * @return	mixed
      */
-    private function forwardOrRedirect()
+    private function forwardOrRedirect() // no return type as mixed is PHP 8 only
     {
         $request = Craft::$app->getRequest();
         $forwardUrl = $request->getParam('forward');
@@ -302,7 +302,7 @@ private function forwardOrRedirect()
      * @access	private
      * @return	mixed
      */
-    private function mapProfile()
+    private function mapProfile() // no return type as mixed is PHP 8 only
     {
         $request = Craft::$app->getRequest();
         $profileParams = $request->getParam('profile');
diff --git a/src/fields/ListField.php b/src/fields/ListField.php
index 601d59d..131a5d1 100644
--- a/src/fields/ListField.php
+++ b/src/fields/ListField.php
@@ -70,7 +70,7 @@ public function getInputHtml($value, ElementInterface $element = null): string
      * @param	elementinterface	$element	Default: null
      * @return	mixed
      */
-    public function normalizeValue($value, ElementInterface $element = null)
+    public function normalizeValue($value, ElementInterface $element = null) // no return type as mixed is PHP 8 only
     {
         if ($value) {
             $o = json_decode($value);
diff --git a/src/fields/ListsField.php b/src/fields/ListsField.php
index 8fd2779..a1425ba 100644
--- a/src/fields/ListsField.php
+++ b/src/fields/ListsField.php
@@ -78,7 +78,7 @@ public function getInputHtml($values, ElementInterface $element = null): string
      * @param	elementinterface	$element	Default: null
      * @return	mixed
      */
-    public function normalizeValue($values, ElementInterface $element = null)
+    public function normalizeValue($values, ElementInterface $element = null) // no return type as mixed is PHP 8 only
     {
         if ($values && !is_array($values)) {
             $o = json_decode($values);
diff --git a/src/models/Base.php b/src/models/Base.php
index 6f6a206..c10ea4f 100644
--- a/src/models/Base.php
+++ b/src/models/Base.php
@@ -62,7 +62,7 @@ public function setCustomProperties($properties): void
      * @param	boolean	$recursive	Default: true
      * @return	mixed
      */
-    public function toArray(array $fields = [], array $expand = [], $recursive = true)
+    public function toArray(array $fields = [], array $expand = [], $recursive = true) // no return type as mixed is PHP 8 only
     {
         $arr = parent::toArray($fields, $expand, $recursive);
 
diff --git a/src/services/Api.php b/src/services/Api.php
index 9ee5219..6faf04c 100644
--- a/src/services/Api.php
+++ b/src/services/Api.php
@@ -122,7 +122,7 @@ public function getPersonIdfromEmail(string $email): ?string
      * @param	array	$params	Array of values to update
      * @return	mixed
      */
-    public function updateProfile(string $id, array $params)
+    public function updateProfile(string $id, array $params) // no return type as mixed is PHP 8 only
     {
         $profile = [];
         
@@ -233,7 +233,7 @@ private function encode($params): string
      * @access	public
      * @return	mixed
      */
-    public function getLists()
+    public function getLists() // no return type as mixed is PHP 8 only
     {
 
         if (is_null($this->cachedLists)) {
@@ -294,7 +294,7 @@ public function profileInList($listId, $email): int
      * @param	boolean    	$useSubscribeEndpoint	Default: false
      * @return	mixed
      */
-    public function addProfileToList(KlaviyoList &$list, Profile &$profile, $useSubscribeEndpoint = false)
+    public function addProfileToList(KlaviyoList &$list, Profile &$profile, $useSubscribeEndpoint = false) // no return type as mixed is PHP 8 only
     {
         if (!$profile->hasEmail()) {
             throw new Exception('You must identify a user by email.');
@@ -329,7 +329,7 @@ public function addProfileToList(KlaviyoList &$list, Profile &$profile, $useSubs
      * @param	mixed	$response	
      * @return	mixed
      */
-    private function getObjectResponse($response)
+    private function getObjectResponse($response) // no return type as mixed is PHP 8 only
     {
         $content = $response->getBody()->getContents();
         if (isset($content)) {
diff --git a/src/services/Base.php b/src/services/Base.php
index 87eabb9..41f288e 100644
--- a/src/services/Base.php
+++ b/src/services/Base.php
@@ -20,7 +20,7 @@ abstract class Base extends Component
      * @param	mixed	$name	
      * @return	mixed
      */
-    protected function getSetting($name)
+    protected function getSetting($name) // no return type as mixed only works above PHP 8
     {
         if (is_null($this->settings)) {
             $this->settings = Plugin::getInstance()->settings;
diff --git a/src/services/Cart.php b/src/services/Cart.php
index fad1e1c..72149a7 100644
--- a/src/services/Cart.php
+++ b/src/services/Cart.php
@@ -19,7 +19,7 @@ class Cart extends Base
      * @param	mixed	$number	
      * @return	mixed
      */
-    public function restore($number)
+    public function restore($number) // no return type as mixed is PHP 8 only
     {
         $commerceInstance = Commerce::getInstance();
 
diff --git a/src/services/Track.php b/src/services/Track.php
index e46fe82..de6879d 100644
--- a/src/services/Track.php
+++ b/src/services/Track.php
@@ -85,7 +85,7 @@ private function isInGroup($selectedGroups, $userGroups): bool
      * @param	mixed	$context  	Default: null
      * @return	mixed
      */
-    protected function createProfile($params, $eventName = null, $context = null): mixed
+    protected function createProfile($params, $eventName = null, $context = null) // no return type as mixed is PHP 8 only
     {
         $profile = new Profile($params);
 
@@ -345,7 +345,7 @@ public function trackOrder($eventName, $order, $profile = null, $timestamp = nul
      * @param	string	$event	Default: ''
      * @return	mixed
      */
-    protected function getOrderDetails($order, $event = ''): mixed
+    protected function getOrderDetails($order, $event = '') // no return type as mixed is PHP 8 only
     {
         $settings = Plugin::getInstance()->settings;
 
diff --git a/src/variables/Variable.php b/src/variables/Variable.php
index 39795d2..b0846e5 100644
--- a/src/variables/Variable.php
+++ b/src/variables/Variable.php
@@ -18,7 +18,7 @@ class Variable
      * @access	public
      * @return	mixed
      */
-    public function lists()
+    public function lists() // no return type as mixed is PHP 8 only
     {
         if (is_null($this->lists)) {
             try {
@@ -43,7 +43,7 @@ public function lists()
      * @access	public
      * @return	mixed
      */
-    public function error()
+    public function error() // no return type as mixed is PHP 8 only
     {
         return $this->error;
     }