Lỗi error reading skeleton json file for skeletondata asset

After update to 3.8, when I want to create a SkeletonAnimation, it always give me an error at SkeletonJson.c line 939.

This is the line I ended up for [attachmentsMap = Json_getItem[skinMap, "attachments"]->child; attachmentsMap; attachmentsMap = attachmentsMap->next] {

And this is how I create my skeleton node. skeletonNode = [SkeletonAnimation skeletonWithFile:skeleton atlasFile:atlas scale:scale];

Anyway, I am using spine version 3.7.94. From what I have discovered, there's a difference about json skeleton from 3.8 and 3.7. In each skin node, there is an attachments. So my question is, how to support skeleton from previous spine version when I need the 3.8 runtime feature like spSkin_addSkin?

Skeleton 'girl' [exported with Spine 3.8.12-beta] may be incompatible with your runtime version: spine-csharp v3.7
UnityEngine.Debug:LogWarningFormat[String, Object[]]
Spine.Unity.Editor.AssetUtility:IsSpineData[TextAsset] [at Assets/Spine/Editor/spine-unity/Editor/SpineEditorUtilities.cs:1271]
Spine.Unity.Editor.AssetUtility:ImportSpineContent[String[], Boolean] [at Assets/Spine/Editor/spine-unity/Editor/SpineEditorUtilities.cs:847]
Spine.Unity.Editor.AssetUtility:HandleOnPostprocessAllAssets[String[]] [at Assets/Spine/Editor/spine-unity/Editor/SpineEditorUtilities.cs:673]
Spine.Unity.Editor.SpineEditorUtilities:OnPostprocessAllAssets[String[], String[], String[], String[]] [at Assets/Spine/Editor/spine-unity/Editor/SpineEditorUtilities.cs:218]
UnityEditor.AssetPostprocessingInternal:PostprocessAllAssets[String[], String[], String[], String[], String[]]
UnityEditorInternal.InternalEditorUtility:ProjectWindowDrag[HierarchyProperty, Boolean]
UnityEngine.GUIUtility:ProcessEvent[Int32, IntPtr]

But I'm sure I've imported the 3.8 package.