diff --git a/Mu3Mods.csproj b/Mu3Mods.csproj
index 0e6bb87..93d3332 100644
--- a/Mu3Mods.csproj
+++ b/Mu3Mods.csproj
@@ -2,7 +2,7 @@
   <PropertyGroup>
     <TargetFramework>net35</TargetFramework>
     <Company>7EVENDAYS⇔HOLIDAYS</Company>
-    <Version>2.3.0</Version>
+    <Version>2.3.1</Version>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <LangVersion>latest</LangVersion>
     <Platforms>x64</Platforms>
diff --git a/SortByInternalDifficulty/MU3.User/patch_UserDetail.cs b/SortByInternalDifficulty/MU3.User/patch_UserDetail.cs
new file mode 100644
index 0000000..11cd792
--- /dev/null
+++ b/SortByInternalDifficulty/MU3.User/patch_UserDetail.cs
@@ -0,0 +1,20 @@
+using MU3.Client;
+using MU3.DB;
+
+namespace MU3.User;
+class patch_UserDetail: UserDetail {
+    public extern void orig_copyTo(UserData userDetail);
+    public new void copyTo(UserData userDetail) {
+        orig_copyTo(userDetail);
+
+        // Attempting to use a profile with InternalLevel sorting enabled
+        // causes unpatched clients to crash thanks to enormous incompetence
+        // of Sxga's interns. So, unfortunately, this value has to be discarded.
+        // See:
+        // * MusicSelectViewDataList._sort1 set
+        // * UserDetail.copyFrom()
+        if(userDetail.tabSetting == (int)patch_MusicSort1ID.InternalLevel) {
+            userDetail.tabSetting = (int)patch_MusicSort1ID.Level;
+        }
+    }
+}
diff --git a/SortByInternalDifficulty/MU3.ViewData/patch_MusicSelectViewDataList.cs b/SortByInternalDifficulty/MU3.ViewData/patch_MusicSelectViewDataList.cs
index 69d1fdf..98c0712 100644
--- a/SortByInternalDifficulty/MU3.ViewData/patch_MusicSelectViewDataList.cs
+++ b/SortByInternalDifficulty/MU3.ViewData/patch_MusicSelectViewDataList.cs
@@ -15,6 +15,7 @@ class patch_MusicSelectViewDataList: MusicSelectViewDataList {
     private CompareProc _compareProc1;
     private CompareProc _compareProc2;
     private GetCategoryNameProc _getCategoryNameProc;
+    private PropertyInfo _reMasterPi = null;
 
     private extern void orig_set__sort1(MusicSort1ID value);
     private extern void orig_set__sort2(MusicSort2ID value);
@@ -36,19 +37,18 @@ class patch_MusicSelectViewDataList: MusicSelectViewDataList {
         }
     }
 
-    private PropertyInfo reMasterPi = null;
     private bool isReMaster(Data.MusicData d) {
         // Fall back for pre-Act3
-        if(reMasterPi == null) {
+        if(_reMasterPi == null) {
             return false;
         }
-        return (bool)reMasterPi.GetValue(d, null);
+        return (bool)_reMasterPi.GetValue(d, null);
     }
 
     public extern void orig_create(GameViewData gameViewData, ChapterSelection chapterSelection, FumenDifficulty difficulty, MusicSort1ID sort1, MusicSort2ID sort2);
 
     public new void create(GameViewData gameViewData, ChapterSelection chapterSelection, FumenDifficulty difficulty, MusicSort1ID sort1, MusicSort2ID sort2) {
-        reMasterPi = typeof(Data.MusicData).GetProperty("isReMaster");
+        _reMasterPi = typeof(Data.MusicData).GetProperty("isReMaster");
         orig_create(gameViewData, chapterSelection, difficulty, sort1, sort2);
     }
 
@@ -100,7 +100,7 @@ class patch_MusicSelectViewDataList: MusicSelectViewDataList {
 
     private extern int orig_getMetaSortKey(MusicSelectViewData d, bool forCategorySort);
     private int getMetaSortKey(MusicSelectViewData d, bool forCategorySort) {
-        if(reMasterPi == null) {
+        if(_reMasterPi == null) {
             return orig_getMetaSortKey(d, forCategorySort);
         }
         var remas = isReMaster(d.musicViewData.data);