diff --git a/Assets/LDtkUnity/Editor/Utility/Artifacts/LDtkConfigData.cs b/Assets/LDtkUnity/Editor/Utility/Artifacts/LDtkConfigData.cs
index e58465b8..228212f0 100644
--- a/Assets/LDtkUnity/Editor/Utility/Artifacts/LDtkConfigData.cs
+++ b/Assets/LDtkUnity/Editor/Utility/Artifacts/LDtkConfigData.cs
@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Text;
+using UnityEditor;
 using UnityEngine;
 
 namespace LDtkUnity.Editor
@@ -23,7 +24,7 @@ internal struct LDtkConfigData
         internal string WriteJson(string projectAssetPath)
         {
             string writePath = GetPath(projectAssetPath);
-            string json = JsonUtility.ToJson(this, true);
+            string json = EditorJsonUtility.ToJson(this, true);
             byte[] byteArray = Encoding.UTF8.GetBytes(json);
             
             LDtkPathUtility.TryCreateDirectoryForFile(writePath);
@@ -41,7 +42,10 @@ internal static LDtkConfigData ReadJson(string assetPath)
 
             byte[] bytes = File.ReadAllBytes(assetPath);
             string json = Encoding.UTF8.GetString(bytes);
-            return JsonUtility.FromJson<LDtkConfigData>(json);
+
+            LDtkConfigData data = new LDtkConfigData();
+            EditorJsonUtility.FromJsonOverwrite(json, data);
+            return data;
         }
         
         internal static string GetPath(string projectAssetPath)
diff --git a/Assets/LDtkUnity/Samples~/Samples/SeparateLevelFiles/SeparateLevelFiles_Config.ldtkc b/Assets/LDtkUnity/Samples~/Samples/SeparateLevelFiles/SeparateLevelFiles_Config.ldtkc
index 3836910e..7b65795a 100644
--- a/Assets/LDtkUnity/Samples~/Samples/SeparateLevelFiles/SeparateLevelFiles_Config.ldtkc
+++ b/Assets/LDtkUnity/Samples~/Samples/SeparateLevelFiles/SeparateLevelFiles_Config.ldtkc
@@ -13,7 +13,9 @@
         {
             "_key": "IntGrid_1",
             "_asset": {
-                "instanceID": 22226
+                "fileID": 11400000,
+                "guid": "85c839224be7398449b593cedc9d81ca",
+                "type": 2
             }
         }
     ],
diff --git a/Assets/Tests/Misc/OtherTechTests/DependencyTest/TestIntGridValueDependency/TestIntGridValueDependency_Config.ldtkc b/Assets/Tests/Misc/OtherTechTests/DependencyTest/TestIntGridValueDependency/TestIntGridValueDependency_Config.ldtkc
index 1e9b3d3b..96ee7f61 100644
--- a/Assets/Tests/Misc/OtherTechTests/DependencyTest/TestIntGridValueDependency/TestIntGridValueDependency_Config.ldtkc
+++ b/Assets/Tests/Misc/OtherTechTests/DependencyTest/TestIntGridValueDependency/TestIntGridValueDependency_Config.ldtkc
@@ -13,19 +13,25 @@
         {
             "_key": "IntGrid_1",
             "_asset": {
-                "instanceID": 29410
+                "fileID": 11400000,
+                "guid": "019c844af99991d409a134bcc556b3b1",
+                "type": 2
             }
         },
         {
             "_key": "IntGrid_2",
             "_asset": {
-                "instanceID": 28118
+                "fileID": 11400000,
+                "guid": "aee5cec04e488604cb16a7da061946bc",
+                "type": 2
             }
         },
         {
             "_key": "IntGrid_3",
             "_asset": {
-                "instanceID": 24110
+                "fileID": 11400000,
+                "guid": "62504a226f3487f49af1e37703e72136",
+                "type": 2
             }
         }
     ],
diff --git a/Assets/Tests/Misc/OtherTechTests/LevelsVania/LevelsVania_Config.ldtkc b/Assets/Tests/Misc/OtherTechTests/LevelsVania/LevelsVania_Config.ldtkc
index b579707c..12dd7638 100644
--- a/Assets/Tests/Misc/OtherTechTests/LevelsVania/LevelsVania_Config.ldtkc
+++ b/Assets/Tests/Misc/OtherTechTests/LevelsVania/LevelsVania_Config.ldtkc
@@ -13,7 +13,9 @@
         {
             "_key": "Collisions_1",
             "_asset": {
-                "instanceID": 25948
+                "fileID": 11400000,
+                "guid": "608aedeab5fb3ac48959b083b4ecd7c1",
+                "type": 2
             }
         },
         {
@@ -27,37 +29,49 @@
         {
             "_key": "Item",
             "_asset": {
-                "instanceID": 30982
+                "fileID": 6381717676898315408,
+                "guid": "154ba3503afd20d4580ff3f817fd2177",
+                "type": 3
             }
         },
         {
             "_key": "Player",
             "_asset": {
-                "instanceID": 33704
+                "fileID": 6381717676898315408,
+                "guid": "2c40888790883084b832d4183474c09a",
+                "type": 3
             }
         },
         {
             "_key": "Exit",
             "_asset": {
-                "instanceID": 31998
+                "fileID": 6381717676898315408,
+                "guid": "109ac9123036bb24ca5866d7aa81f4b3",
+                "type": 3
             }
         },
         {
             "_key": "SecretArea",
             "_asset": {
-                "instanceID": 31288
+                "fileID": 6381717676898315408,
+                "guid": "455e2726c152eb946bab81090f7c0afa",
+                "type": 3
             }
         },
         {
             "_key": "Teleport",
             "_asset": {
-                "instanceID": 30554
+                "fileID": 6381717676898315408,
+                "guid": "9958dbc3bfc14c64ba545adf3467ed50",
+                "type": 3
             }
         },
         {
             "_key": "Ladder",
             "_asset": {
-                "instanceID": 30794
+                "fileID": 6381717676898315408,
+                "guid": "4bd923e45ce962547bb6ae2dd76a5984",
+                "type": 3
             }
         }
     ]
diff --git a/Assets/Tests/Misc/OtherTechTests/TestAllFieldsLevels/TestAllFieldsLevels_Config.ldtkc b/Assets/Tests/Misc/OtherTechTests/TestAllFieldsLevels/TestAllFieldsLevels_Config.ldtkc
index d083fc40..00b42870 100644
--- a/Assets/Tests/Misc/OtherTechTests/TestAllFieldsLevels/TestAllFieldsLevels_Config.ldtkc
+++ b/Assets/Tests/Misc/OtherTechTests/TestAllFieldsLevels/TestAllFieldsLevels_Config.ldtkc
@@ -14,19 +14,25 @@
         {
             "_key": "TestAllFields",
             "_asset": {
-                "instanceID": 43784
+                "fileID": 2518318380925621618,
+                "guid": "3222c3d6e0104884eb44c4821f66e354",
+                "type": 3
             }
         },
         {
             "_key": "NoFields",
             "_asset": {
-                "instanceID": 43824
+                "fileID": 2518318380925621618,
+                "guid": "be7f9038a4c1bc04d9d62adff8d0cab8",
+                "type": 3
             }
         },
         {
             "_key": "TestAllNullable",
             "_asset": {
-                "instanceID": 43832
+                "fileID": 2518318380925621618,
+                "guid": "55ee5e096e24b4542bc1968b36e6c019",
+                "type": 3
             }
         }
     ]
diff --git a/Assets/Tests/Misc/OtherTechTests/Test_file_for_API_showing_all_featuresLevels/Test_file_for_API_showing_all_featuresLevels_Config.ldtkc b/Assets/Tests/Misc/OtherTechTests/Test_file_for_API_showing_all_featuresLevels/Test_file_for_API_showing_all_featuresLevels_Config.ldtkc
index f0bfad6d..ae0d4624 100644
--- a/Assets/Tests/Misc/OtherTechTests/Test_file_for_API_showing_all_featuresLevels/Test_file_for_API_showing_all_featuresLevels_Config.ldtkc
+++ b/Assets/Tests/Misc/OtherTechTests/Test_file_for_API_showing_all_featuresLevels/Test_file_for_API_showing_all_featuresLevels_Config.ldtkc
@@ -45,31 +45,41 @@
         {
             "_key": "EntityFieldsTest",
             "_asset": {
-                "instanceID": 70644
+                "fileID": 8271057754295682963,
+                "guid": "8edc4af9ae4379948ac2d95a7603e233",
+                "type": 3
             }
         },
         {
             "_key": "Labels",
             "_asset": {
-                "instanceID": 70646
+                "fileID": 8271057754295682963,
+                "guid": "651dd273af932094fbe35791264dcfa4",
+                "type": 3
             }
         },
         {
             "_key": "RectRegion",
             "_asset": {
-                "instanceID": 70648
+                "fileID": 8271057754295682963,
+                "guid": "e355c9bebb8a0fe458316f819cb5df56",
+                "type": 3
             }
         },
         {
             "_key": "CircleRegion",
             "_asset": {
-                "instanceID": 70650
+                "fileID": 8271057754295682963,
+                "guid": "9a9f4260bc1dd5444a09370d4abf42f8",
+                "type": 3
             }
         },
         {
             "_key": "EntityRefTest",
             "_asset": {
-                "instanceID": 70650
+                "fileID": 8271057754295682963,
+                "guid": "9a9f4260bc1dd5444a09370d4abf42f8",
+                "type": 3
             }
         }
     ]