it is done

core/src/mindustry/io/versions/Save2.java

@@ -0,0 +1,35 @@
+package mindustry.io.versions;
+
+import mindustry.ctype.ContentType;
+import mindustry.entities.traits.*;
+import mindustry.io.*;
+import mindustry.type.TypeID;
+
+import java.io.*;
+
+import static mindustry.Vars.content;
+
+public class Save2 extends SaveVersion{
+
+    public Save2(){
+        super(2);
+    }
+
+    @Override
+    public void readEntities(DataInput stream) throws IOException{
+        byte groups = stream.readByte();
+
+        for(int i = 0; i < groups; i++){
+            int amount = stream.readInt();
+            for(int j = 0; j < amount; j++){
+                //TODO throw exception on read fail
+                readChunk(stream, true, in -> {
+                    byte typeid = in.readByte();
+                    byte version = in.readByte();
+                    SaveTrait trait = (SaveTrait)content.<TypeID>getByID(ContentType.typeid, typeid).constructor.get();
+                    trait.readSave(in, version);
+                });
+            }
+        }
+    }
+}