diff --git a/UPGRADE-0.X.md b/UPGRADE-0.X.md
index 832a68c..b0c51fb 100644
--- a/UPGRADE-0.X.md
+++ b/UPGRADE-0.X.md
@@ -1,5 +1,75 @@
 # UPGRADE FROM `v0.1.0` TO `v0.X`
 
+## UPGRADE FROM `v0.9.0` TO `v0.10.0`
+
+> **BC** Method Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareTrait#__construct() was removed
+
+There was a bug due to a __construct method on the trait CustomerActiveCampaignAwareTrait. The constructor of the trait was never called. So that 
+the channelCustomers property was never initialized, or it was initialized to a null value. Even if it was a null value this was then used in a foreach, and it will trigger a deprecation error. 
+This bug has been fixed in this release. If you use the trait you can proceed in two ways:
+
+1 - You can import the channelCustomersInitializers method and call it in the constructor of your entity. The result will be like this:
+```php
+<?php
+
+namespace App\Entity\Customer;
+
+use Doctrine\ORM\Mapping as ORM;
+use Sylius\Component\Core\Model\Customer as BaseCustomer;
+use Webgriffe\SyliusActiveCampaignPlugin\Model\ActiveCampaignAwareTrait;
+use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareInterface;
+use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareTrait;
+
+/**
+ * @ORM\Entity
+ * @ORM\Table(name="sylius_customer")
+ */
+class Customer extends BaseCustomer implements CustomerActiveCampaignAwareInterface
+{
+    use ActiveCampaignAwareTrait;
+    use CustomerActiveCampaignAwareTrait {
+        CustomerActiveCampaignAwareTrait::channelCustomersInitializers as private __channelCustomersInitializers;
+    }
+
+    public function __construct()
+    {
+        parent::__construct();
+        $this->__channelCustomersInitializers();
+    }
+}
+```
+   
+2 - If you prefer you can avoid to import the channelCustomersInitializers method and initialize yourself the
+   channelCustomers property in the constructor. The result will be like this:
+```php
+<?php
+
+namespace App\Entity\Customer;
+
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\ORM\Mapping as ORM;
+use Sylius\Component\Core\Model\Customer as BaseCustomer;
+use Webgriffe\SyliusActiveCampaignPlugin\Model\ActiveCampaignAwareTrait;
+use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareInterface;
+use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareTrait;
+
+/**
+ * @ORM\Entity
+ * @ORM\Table(name="sylius_customer")
+ */
+class Customer extends BaseCustomer implements CustomerActiveCampaignAwareInterface
+{
+    use ActiveCampaignAwareTrait;
+    use CustomerActiveCampaignAwareTrait;
+
+    public function __construct()
+    {
+        parent::__construct();
+        $this->channelCustomers = new ArrayCollection();
+    }
+}
+```
+
 ## UPGRADE FROM `v0.8.0` TO `v0.9.0`
 
 Some services have been removed, please check if you are using them in your application and replace them:
diff --git a/docs/installation.md b/docs/installation.md
index 5366e16..c1346d7 100644
--- a/docs/installation.md
+++ b/docs/installation.md
@@ -50,6 +50,40 @@ nav_order: 2
     use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareInterface;
     use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareTrait;
 	
+    /**
+     * @ORM\Entity
+     * @ORM\Table(name="sylius_customer")
+     */
+    class Customer extends BaseCustomer implements CustomerActiveCampaignAwareInterface
+    {
+        use ActiveCampaignAwareTrait;
+        use CustomerActiveCampaignAwareTrait {
+            CustomerActiveCampaignAwareTrait::channelCustomersInitializers as private __channelCustomersInitializers;
+        }
+   
+        public function __construct()
+        {
+            parent::__construct();
+            $this->__channelCustomersInitializers();
+        }
+    }
+    ```
+   
+   If you prefer you can avoid to import the channelCustomersInitializers method and initialize yourself the
+   channelCustomers property in the constructor. The result will be like this:
+   
+    ```php
+    <?php
+	
+    namespace App\Entity\Customer;
+	
+    use Doctrine\Common\Collections\ArrayCollection;
+    use Doctrine\ORM\Mapping as ORM;
+    use Sylius\Component\Core\Model\Customer as BaseCustomer;
+    use Webgriffe\SyliusActiveCampaignPlugin\Model\ActiveCampaignAwareTrait;
+    use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareInterface;
+    use Webgriffe\SyliusActiveCampaignPlugin\Model\CustomerActiveCampaignAwareTrait;
+	
     /**
      * @ORM\Entity
      * @ORM\Table(name="sylius_customer")
@@ -58,6 +92,12 @@ nav_order: 2
     {
         use ActiveCampaignAwareTrait;
         use CustomerActiveCampaignAwareTrait;
+   
+        public function __construct()
+        {
+            parent::__construct();
+            $this->channelCustomers = new ArrayCollection();
+        }
     }
     ```
 
diff --git a/src/Model/CustomerActiveCampaignAwareTrait.php b/src/Model/CustomerActiveCampaignAwareTrait.php
index 4b83ef3..b7b9a56 100644
--- a/src/Model/CustomerActiveCampaignAwareTrait.php
+++ b/src/Model/CustomerActiveCampaignAwareTrait.php
@@ -18,9 +18,8 @@ trait CustomerActiveCampaignAwareTrait
      */
     protected $channelCustomers;
 
-    public function __construct()
+    private function channelCustomersInitializers(): void
     {
-        parent::__construct();
         $this->channelCustomers = new ArrayCollection();
     }
 
diff --git a/tests/Application/src/Entity/Customer/Customer.php b/tests/Application/src/Entity/Customer/Customer.php
index f279769..4eba167 100644
--- a/tests/Application/src/Entity/Customer/Customer.php
+++ b/tests/Application/src/Entity/Customer/Customer.php
@@ -16,5 +16,13 @@
 class Customer extends BaseCustomer implements CustomerInterface
 {
     use ActiveCampaignAwareTrait;
-    use CustomerActiveCampaignAwareTrait;
+    use CustomerActiveCampaignAwareTrait {
+        CustomerActiveCampaignAwareTrait::channelCustomersInitializers as private __channelCustomersInitializers;
+    }
+
+    public function __construct()
+    {
+        parent::__construct();
+        $this->__channelCustomersInitializers();
+    }
 }