diff --git a/composer.json b/composer.json
index 9004b18..c2d731a 100644
--- a/composer.json
+++ b/composer.json
@@ -12,11 +12,11 @@
     "homepage": "https://github.com/alariva/laravel-modelmerge",
     "keywords": ["Laravel", "ModelMerge"],
     "require": {
-        "illuminate/support": "~5",
-        "illuminate/database": "~5"
+        "illuminate/support": "~11",
+        "illuminate/database": "~11"
     },
     "require-dev": {
-        "phpunit/phpunit": "~6.0",
+        "phpunit/phpunit": "~9.4|^10.4",
         "orchestra/testbench": "~3.5"
     },
     "autoload": {
diff --git a/src/ModelMerge.php b/src/ModelMerge.php
index a2891ea..5d35038 100644
--- a/src/ModelMerge.php
+++ b/src/ModelMerge.php
@@ -274,8 +274,13 @@ public function transferRelationships()
 
     public function transferChilds($relationship)
     {
-        foreach ($this->modelB->$relationship as $child) {
-            $this->modelA->$relationship()->save($child);
+        $children = $this->modelB->$relationship;
+
+        // Check if the relationship is not null or ensure it's iterable
+        if ($children) {
+            foreach ($children as $child) {
+                $this->modelA->$relationship()->save($child);
+            }
         }
     }