diff --git a/src/Rbac/Role/HierarchicalRole.php b/src/Rbac/Role/HierarchicalRole.php
index 714312f..5ab2432 100644
--- a/src/Rbac/Role/HierarchicalRole.php
+++ b/src/Rbac/Role/HierarchicalRole.php
@@ -9,8 +9,6 @@
 
 namespace Rbac\Role;
 
-use Traversable;
-
 /**
  * Simple implementation for a hierarchical role
  */
@@ -19,12 +17,12 @@ class HierarchicalRole extends Role implements HierarchicalRoleInterface
     /**
      * @var array|RoleInterface[]
      */
-    protected array $children = [];
+    protected $children = [];
 
     /**
      * {@inheritDoc}
      */
-    public function hasChildren(): bool
+    public function hasChildren()
     {
         return !empty($this->children);
     }
@@ -32,7 +30,7 @@ public function hasChildren(): bool
     /**
      * {@inheritDoc}
      */
-    public function getChildren(): Traversable|array
+    public function getChildren()
     {
         return $this->children;
     }
@@ -42,7 +40,7 @@ public function getChildren(): Traversable|array
      *
      * @param RoleInterface $child
      */
-    public function addChild(RoleInterface $child): void
+    public function addChild(RoleInterface $child)
     {
         $this->children[$child->getName()] = $child;
     }
diff --git a/src/Rbac/Role/HierarchicalRoleInterface.php b/src/Rbac/Role/HierarchicalRoleInterface.php
index f63589d..9dbb5ea 100644
--- a/src/Rbac/Role/HierarchicalRoleInterface.php
+++ b/src/Rbac/Role/HierarchicalRoleInterface.php
@@ -23,12 +23,12 @@ interface HierarchicalRoleInterface extends RoleInterface
      *
      * @return bool
      */
-    public function hasChildren(): bool;
+    public function hasChildren();
 
     /**
      * Get child roles
      *
      * @return array|RoleInterface[]|Traversable
      */
-    public function getChildren(): array|Traversable;
+    public function getChildren();
 }
diff --git a/src/Rbac/Role/Role.php b/src/Rbac/Role/Role.php
index 1b855dd..f2b5a3f 100644
--- a/src/Rbac/Role/Role.php
+++ b/src/Rbac/Role/Role.php
@@ -18,19 +18,19 @@ class Role implements RoleInterface
     /**
      * @var string
      */
-    protected string $name;
+    protected $name;
 
     /**
      * @var string[]
      */
-    protected array $permissions = [];
+    protected $permissions = [];
 
     /**
      * Constructor
      *
      * @param string $name
      */
-    public function __construct(string $name)
+    public function __construct($name)
     {
         $this->name = (string) $name;
     }
@@ -38,7 +38,7 @@ public function __construct(string $name)
     /**
      * {@inheritDoc}
      */
-    public function getName(): string
+    public function getName()
     {
         return $this->name;
     }
@@ -48,7 +48,7 @@ public function getName(): string
      *
      * @param string $permission
      */
-    public function addPermission(string $permission): void
+    public function addPermission($permission)
     {
         $this->permissions[(string) $permission] = $permission;
     }
@@ -56,10 +56,10 @@ public function addPermission(string $permission): void
     /**
      * Checks if a permission exists for this role
      *
-     * @param mixed $permission
+     * @param  string $permission
      * @return bool
      */
-    public function hasPermission(mixed $permission): bool
+    public function hasPermission($permission)
     {
         return isset($this->permissions[(string) $permission]);
     }
diff --git a/src/Rbac/Role/RoleInterface.php b/src/Rbac/Role/RoleInterface.php
index 59aabc5..04f23fd 100644
--- a/src/Rbac/Role/RoleInterface.php
+++ b/src/Rbac/Role/RoleInterface.php
@@ -21,7 +21,7 @@ interface RoleInterface
      *
      * @return string
      */
-    public function getName(): string;
+    public function getName();
 
     /**
      * Checks if a permission exists for this role (it does not check child roles)
@@ -29,5 +29,5 @@ public function getName(): string;
      * @param  mixed $permission
      * @return bool
      */
-    public function hasPermission(mixed $permission): bool;
+    public function hasPermission($permission);
 }
diff --git a/src/Rbac/Traversal/Strategy/GeneratorStrategy.php b/src/Rbac/Traversal/Strategy/GeneratorStrategy.php
index 4c1f224..63574f0 100644
--- a/src/Rbac/Traversal/Strategy/GeneratorStrategy.php
+++ b/src/Rbac/Traversal/Strategy/GeneratorStrategy.php
@@ -24,7 +24,7 @@ class GeneratorStrategy implements TraversalStrategyInterface
      * @param  RoleInterface[]|Traversable $roles
      * @return Generator
      */
-    public function getRolesIterator($roles): Generator
+    public function getRolesIterator($roles)
     {
         foreach ($roles as $role) {
             yield $role;
diff --git a/src/Rbac/Traversal/Strategy/RecursiveRoleIteratorStrategy.php b/src/Rbac/Traversal/Strategy/RecursiveRoleIteratorStrategy.php
index 55e19e0..93b3a52 100644
--- a/src/Rbac/Traversal/Strategy/RecursiveRoleIteratorStrategy.php
+++ b/src/Rbac/Traversal/Strategy/RecursiveRoleIteratorStrategy.php
@@ -22,7 +22,7 @@ class RecursiveRoleIteratorStrategy implements TraversalStrategyInterface
      * @param  RoleInterface[]           $roles
      * @return RecursiveIteratorIterator
      */
-    public function getRolesIterator($roles): RecursiveIteratorIterator
+    public function getRolesIterator($roles)
     {
         return new RecursiveIteratorIterator(
             new RecursiveRoleIterator($roles),
diff --git a/src/Rbac/Traversal/Strategy/TraversalStrategyInterface.php b/src/Rbac/Traversal/Strategy/TraversalStrategyInterface.php
index a8213cd..dfe5046 100644
--- a/src/Rbac/Traversal/Strategy/TraversalStrategyInterface.php
+++ b/src/Rbac/Traversal/Strategy/TraversalStrategyInterface.php
@@ -21,5 +21,5 @@ interface TraversalStrategyInterface
      * @param  RoleInterface[]|Traversable
      * @return Traversable
      */
-    public function getRolesIterator($roles): Traversable;
+    public function getRolesIterator($roles);
 }