diff --git a/Controller.php b/Controller.php
index 0d0197a..722a51b 100644
--- a/Controller.php
+++ b/Controller.php
@@ -40,7 +40,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string
      * @since 1.0.0
      */
-    /* public */ const MODULE_PATH = __DIR__;
+    public const MODULE_PATH = __DIR__;
 
     /**
      * Module version.
@@ -48,7 +48,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string
      * @since 1.0.0
      */
-    /* public */ const MODULE_VERSION = '1.0.0';
+    public const MODULE_VERSION = '1.0.0';
 
     /**
      * Module name.
@@ -56,7 +56,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string
      * @since 1.0.0
      */
-    /* public */ const MODULE_NAME = 'Billing';
+    public const MODULE_NAME = 'Billing';
 
     /**
      * Module id.
@@ -64,7 +64,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var int
      * @since 1.0.0
      */
-    /* public */ const MODULE_ID = 1005100000;
+    public const MODULE_ID = 1005100000;
 
     /**
      * Providing.
diff --git a/Models/InvoiceStatus.php b/Models/InvoiceStatus.php
index ba70ec1..cc20771 100644
--- a/Models/InvoiceStatus.php
+++ b/Models/InvoiceStatus.php
@@ -26,9 +26,9 @@ use phpOMS\Stdlib\Base\Enum;
  */
 abstract class InvoiceStatus extends Enum
 {
-    /* public */ const ACTIVE   = 1;
-    /* public */ const ARCHIVED = 2;
-    /* public */ const DELETED  = 4;
-    /* public */ const DONE     = 8;
-    /* public */ const DRAFT    = 16;
+    public const ACTIVE   = 1;
+    public const ARCHIVED = 2;
+    public const DELETED  = 4;
+    public const DONE     = 8;
+    public const DRAFT    = 16;
 }
diff --git a/Models/InvoiceType.php b/Models/InvoiceType.php
index feb881e..4de6b2e 100644
--- a/Models/InvoiceType.php
+++ b/Models/InvoiceType.php
@@ -26,10 +26,10 @@ use phpOMS\Stdlib\Base\Enum;
  */
 abstract class InvoiceType extends Enum
 {
-    /* public */ const BILL               = 1;
-    /* public */ const DELIVERY_NOTE      = 2;
-    /* public */ const CREDIT_NOTE        = 3;
-    /* public */ const DEBIT_NOTE         = 4;
-    /* public */ const OFFER              = 5;
-    /* public */ const ORDER_CONFIRMATION = 6;
+    public const BILL               = 1;
+    public const DELIVERY_NOTE      = 2;
+    public const CREDIT_NOTE        = 3;
+    public const DEBIT_NOTE         = 4;
+    public const OFFER              = 5;
+    public const ORDER_CONFIRMATION = 6;
 }