diff --git a/genson/src/main/java/com/owlike/genson/ext/jsr353/JSR353Bundle.java b/genson/src/main/java/com/owlike/genson/ext/jsr353/JSR353Bundle.java
index 46bb3c81..14f4a64f 100644
--- a/genson/src/main/java/com/owlike/genson/ext/jsr353/JSR353Bundle.java
+++ b/genson/src/main/java/com/owlike/genson/ext/jsr353/JSR353Bundle.java
@@ -37,7 +37,7 @@ public Converter<JsonValue> create(Type type, Genson genson) {
     });
   }
 
-  public class JsonValueConverter implements Converter<JsonValue> {
+  public static class JsonValueConverter implements Converter<JsonValue> {
 
     @Override
     public void serialize(JsonValue value, ObjectWriter writer, Context ctx) {
diff --git a/genson/src/main/java/com/owlike/genson/reflect/BeanDescriptor.java b/genson/src/main/java/com/owlike/genson/reflect/BeanDescriptor.java
index 0e17d46a..d6531d94 100644
--- a/genson/src/main/java/com/owlike/genson/reflect/BeanDescriptor.java
+++ b/genson/src/main/java/com/owlike/genson/reflect/BeanDescriptor.java
@@ -126,7 +126,7 @@ public void deserialize(T into, ObjectReader reader, Context ctx) {
           reader.skipValue();
         }
       } else if (unknownPropertyHandler != null) {
-        unknownPropertyHandler.onUnknownProperty(into, propName, reader, ctx);
+        unknownPropertyHandler.readUnknownProperty(propName, reader, ctx).accept(into);
       } else if (failOnMissingProperty) throw missingPropertyException(propName);
       else reader.skipValue();
     }
@@ -157,7 +157,7 @@ protected T _deserWithCtrArgs(ObjectReader reader, Context ctx) {
           reader.skipValue();
         }
       } else if (unknownPropertyHandler != null) {
-        Consumer<T> callback = unknownPropertyHandler.onUnknownProperty(null, propName, reader, ctx);
+        Consumer<T> callback = unknownPropertyHandler.readUnknownProperty(propName, reader, ctx);
         unknownProperties.add(callback);
       } else if (failOnMissingProperty) throw missingPropertyException(propName);
       else reader.skipValue();
@@ -190,9 +190,8 @@ protected T _deserWithCtrArgs(ObjectReader reader, Context ctx) {
         property.mutate(bean, newValues[i]);
       }
     }
-    if (!unknownProperties.isEmpty()) {
-      unknownProperties.forEach(callback -> callback.accept(bean));
-    }
+    unknownProperties.forEach(callback -> callback.accept(bean));
+
     reader.endObject();
     return bean;
   }
diff --git a/genson/src/main/java/com/owlike/genson/reflect/Evolvable.java b/genson/src/main/java/com/owlike/genson/reflect/Evolvable.java
index 43fd87f3..83f03dd7 100644
--- a/genson/src/main/java/com/owlike/genson/reflect/Evolvable.java
+++ b/genson/src/main/java/com/owlike/genson/reflect/Evolvable.java
@@ -1,5 +1,6 @@
 package com.owlike.genson.reflect;
 
+import javax.json.JsonValue;
 import java.util.Map;
 
 /**
@@ -19,12 +20,12 @@ interface Evolvable {
      * @param propName  property name
      * @param propValue property value
      */
-    void addUnknownProperty(String propName, Object propValue);
+    void addUnknownProperty(String propName, JsonValue propValue);
 
     /**
      * Return a map of unknown properties.
      *
      * @return a map of unknown properties
      */
-    Map<String, Object> unknownProperties();
+    Map<String, JsonValue> unknownProperties();
 }
diff --git a/genson/src/main/java/com/owlike/genson/reflect/EvolvableHandler.java b/genson/src/main/java/com/owlike/genson/reflect/EvolvableHandler.java
index b77f562f..c344af8e 100644
--- a/genson/src/main/java/com/owlike/genson/reflect/EvolvableHandler.java
+++ b/genson/src/main/java/com/owlike/genson/reflect/EvolvableHandler.java
@@ -1,11 +1,13 @@
 package com.owlike.genson.reflect;
 
 import com.owlike.genson.Context;
-import com.owlike.genson.GenericType;
+import com.owlike.genson.Converter;
+import com.owlike.genson.ext.jsr353.JSR353Bundle;
 import com.owlike.genson.stream.ObjectReader;
 import com.owlike.genson.stream.ObjectWriter;
 
 import javax.json.JsonValue;
+
 import java.util.Map;
 import java.util.function.Consumer;
 
@@ -25,41 +27,37 @@
  * @author Aleksandar Seovic  2018.05.20
  */
 public class EvolvableHandler implements UnknownPropertyHandler {
-    private static final GenericType<JsonValue> UNKNOWN = new GenericType<JsonValue>() {};
+    private static final Converter<JsonValue> CONVERTER = new JSR353Bundle.JsonValueConverter();
 
     @Override
-    public <T> Consumer<T> onUnknownProperty(T target, String propName, ObjectReader reader, Context ctx) {
-        // TODO: change this to read property as an opaque value, using ObjectReader directly
-        Object propValue = ctx.genson.deserialize(UNKNOWN, reader, ctx);
+    public <T> Consumer<T> readUnknownProperty(String propName, ObjectReader reader, Context ctx) {
+        try {
+            JsonValue propValue = CONVERTER.deserialize(reader, ctx);
 
-        if (target == null) {
-            // this is a bit ugly...
-            // the issue is that we may not have a target object while parsing JSON when using creators,
-            // so we need to store the parsed value somewhere and apply it later
             return objTarget -> {
                 if (objTarget instanceof Evolvable) {
                     ((Evolvable) objTarget).addUnknownProperty(propName, propValue);
                 }
             };
+        } catch (Exception e) {
+            throw new RuntimeException(e);
         }
-
-        if (target instanceof Evolvable) {
-            ((Evolvable) target).addUnknownProperty(propName, propValue);
-        }
-        return null;
     }
 
     @Override
-    public <T> void writeUnknownProperties(T source, ObjectWriter writer, Context ctx) {
-        if (source instanceof Evolvable) {
-            Map<String, Object> props = ((Evolvable) source).unknownProperties();
-            if (props != null) {
-                for (String propName : props.keySet()) {
-                    writer.writeName(propName);
-                    // TODO: change this to write property as an opaque value, using ObjectWriter directly
-                    ctx.genson.serialize(props.get(propName), writer, ctx);
+    public <T> void writeUnknownProperties(T bean, ObjectWriter writer, Context ctx) {
+        try {
+            if (bean instanceof Evolvable) {
+                Map<String, JsonValue> props = ((Evolvable) bean).unknownProperties();
+                if (props != null) {
+                    for (String propName : props.keySet()) {
+                        writer.writeName(propName);
+                        CONVERTER.serialize(props.get(propName), writer, ctx);
+                    }
                 }
             }
+        } catch (Exception e) {
+            throw new RuntimeException(e);
         }
     }
 }
\ No newline at end of file
diff --git a/genson/src/main/java/com/owlike/genson/reflect/EvolvableObject.java b/genson/src/main/java/com/owlike/genson/reflect/EvolvableObject.java
index 4796b127..7256cfdb 100644
--- a/genson/src/main/java/com/owlike/genson/reflect/EvolvableObject.java
+++ b/genson/src/main/java/com/owlike/genson/reflect/EvolvableObject.java
@@ -2,6 +2,7 @@
 
 import com.owlike.genson.annotation.JsonIgnore;
 
+import javax.json.JsonValue;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -12,10 +13,10 @@
  */
 public abstract class EvolvableObject implements Evolvable {
     @JsonIgnore
-    private Map<String, Object> unknownProperties;
+    private Map<String, JsonValue> unknownProperties;
 
     @Override
-    public void addUnknownProperty(String propName, Object propValue) {
+    public void addUnknownProperty(String propName, JsonValue propValue) {
         if (unknownProperties == null) {
             unknownProperties = new HashMap<>();
         }
@@ -23,7 +24,7 @@ public void addUnknownProperty(String propName, Object propValue) {
     }
 
     @Override
-    public Map<String, Object> unknownProperties() {
+    public Map<String, JsonValue> unknownProperties() {
         return unknownProperties;
     }
 }
diff --git a/genson/src/main/java/com/owlike/genson/reflect/UnknownPropertyHandler.java b/genson/src/main/java/com/owlike/genson/reflect/UnknownPropertyHandler.java
index c3bf8e0b..aa6450eb 100644
--- a/genson/src/main/java/com/owlike/genson/reflect/UnknownPropertyHandler.java
+++ b/genson/src/main/java/com/owlike/genson/reflect/UnknownPropertyHandler.java
@@ -29,14 +29,14 @@ public interface UnknownPropertyHandler {
      * property value somewhere so it can be written later by the
      * {@link #writeUnknownProperties} method.
      *
-     * @param target    the object we are deserializing JSON into, if known
      * @param propName  the name of the unknown property
      * @param reader    the ObjectReader to read property value from
      * @param ctx       deserialization context
      *
-     * @return the optional Consumer that will be called once the target object is known
+     * @return the Consumer that will be called with the target bean,
+     *         once the target bean is known
      */
-    <T> Consumer<T> onUnknownProperty(T target, String propName, ObjectReader reader, Context ctx);
+    <T> Consumer<T> readUnknownProperty(String propName, ObjectReader reader, Context ctx);
 
     /**
      * Write unknown properties encountered during deserialization.
@@ -45,12 +45,10 @@ public interface UnknownPropertyHandler {
      * that want to write unknown properties during serialization. The default
      * implementation is a no-op.
      *
-     * @param source  the object we are serializing into JSON
+     * @param bean    the object we are serializing into JSON
      * @param writer  the ObjectReader to read property value from
      * @param ctx     serialization context
-     *
-     * @return a map of unknown properties
      */
-    default <T> void writeUnknownProperties(T source, ObjectWriter writer, Context ctx) {
+    default <T> void writeUnknownProperties(T bean, ObjectWriter writer, Context ctx) {
     }
 }