I waste several hours

core/src/mindustry/io/versions/Save6.java

@@ -1,10 +1,31 @@
 package mindustry.io.versions;
 
+import arc.util.io.*;
 import mindustry.io.*;
+import mindustry.world.*;
 
+import java.io.*;
+
+import static mindustry.Vars.*;
+
+/** This version does not read custom chunk data. */
 public class Save6 extends SaveVersion{
 
     public Save6(){
         super(6);
     }
+
+    @Override
+    public void read(DataInputStream stream, CounterInputStream counter, WorldContext context) throws IOException{
+        region("meta", stream, counter, this::readMeta);
+        region("content", stream, counter, this::readContentHeader);
+
+        try{
+            region("map", stream, counter, in -> readMap(in, context));
+            region("entities", stream, counter, this::readEntities);
+        }finally{
+            content.setTemporaryMapper(null);
+
+        }
+    }
 }