diff --git a/Route4Me Route Optimization Examples/Examples/Orders/AddScheduledOrder.vb b/Route4Me Route Optimization Examples/Examples/Orders/AddScheduledOrder.vb
index b1ba970..b5973eb 100644
--- a/Route4Me Route Optimization Examples/Examples/Orders/AddScheduledOrder.vb	
+++ b/Route4Me Route Optimization Examples/Examples/Orders/AddScheduledOrder.vb	
@@ -21,12 +21,10 @@ Namespace Route4MeSDKTest.Examples
                 .EXT_FIELD_last_name = "Carol",
                 .EXT_FIELD_email = "lcarol654@yahoo.com",
                 .EXT_FIELD_phone = "897946541",
-                .EXT_FIELD_custom_data = (New List(Of Dictionary(Of String, String))() From {
-                        New Dictionary(Of String, String)() From {
+                .EXT_FIELD_custom_data = New Dictionary(Of String, String)() From {
                             {"order_type", "scheduled order"}
-                        }
-                    }).ToArray(),
-                .day_scheduled_for_YYMMDD = "2017-12-20",
+                        },
+                .day_scheduled_for_YYMMDD = DateTime.Now.ToString("yyyy-MM-dd"),
                 .local_time_window_end = 39000,
                 .local_time_window_end_2 = 46200,
                 .local_time_window_start = 37800,
diff --git a/Route4MeSDKLibrary/DataTypes/Order.vb b/Route4MeSDKLibrary/DataTypes/Order.vb
index 7a8caf7..e193790 100644
--- a/Route4MeSDKLibrary/DataTypes/Order.vb
+++ b/Route4MeSDKLibrary/DataTypes/Order.vb
@@ -1,4 +1,5 @@
-Imports Route4MeSDKLibrary.Route4MeSDK.QueryTypes
+Imports Newtonsoft.Json
+Imports Route4MeSDKLibrary.Route4MeSDK.QueryTypes
 Imports System.Runtime.Serialization
 
 Namespace Route4MeSDK.DataTypes
@@ -151,22 +152,27 @@ Namespace Route4MeSDK.DataTypes
         Public Property EXT_FIELD_phone As String
 
         ''' <summary>
-        ''' Custom data
+        ''' Not serialized - for prevention wrong data (e.g. Dictionary(Of String, String)())
         ''' </summary>
-        <DataMember(Name:="EXT_FIELD_custom_data", EmitDefaultValue:=False)>
-        Public Property EXT_FIELD_custom_data() As Dictionary(Of String, String)()
+        <JsonIgnore>
+        Public Property EXT_FIELD_custom_data As Dictionary(Of String, String)
             Get
-                Return _ext_field_custom_data
+                Return If(
+                    EXT_FIELD_custom_data2 IsNot Nothing AndAlso EXT_FIELD_custom_data2.[GetType]() = GetType(Dictionary(Of String, String)),
+                    CType(EXT_FIELD_custom_data2, Dictionary(Of String, String)),
+                    Nothing
+                    )
             End Get
-            Set(ByVal value As Dictionary(Of String, String)())
-                If value.[GetType]() = GetType(Dictionary(Of String, String)()) Then
-                    _ext_field_custom_data = value
-                Else
-                    _ext_field_custom_data = Nothing
-                End If
+            Set(ByVal value As Dictionary(Of String, String))
+                EXT_FIELD_custom_data2 = value
             End Set
         End Property
-        Private _ext_field_custom_data As Dictionary(Of String, String)()
+
+        ''' <summary>
+        ''' Custom data - serialized
+        ''' </summary>
+        <DataMember(Name:="EXT_FIELD_custom_data", EmitDefaultValue:=False)>
+        Private Property EXT_FIELD_custom_data2 As Object
 
         ''' <summary>
         ''' Local timezone string
diff --git a/Route4meSDKLibraryUnitTests/Route4MeManagerUnitTest..vb b/Route4meSDKLibraryUnitTests/Route4MeManagerUnitTest..vb
index b129cca..3f04d93 100644
--- a/Route4meSDKLibraryUnitTests/Route4MeManagerUnitTest..vb
+++ b/Route4meSDKLibraryUnitTests/Route4MeManagerUnitTest..vb
@@ -8955,11 +8955,7 @@ End Class
             .EXT_FIELD_last_name = "Carol",
             .EXT_FIELD_email = "lcarol654@yahoo.com",
             .EXT_FIELD_phone = "897946541",
-            .EXT_FIELD_custom_data = (New List(Of Dictionary(Of String, String))() From {
-                    New Dictionary(Of String, String)() From {
-                        {"order_type", "scheduled order"}
-                    }
-                }).ToArray(),
+            .EXT_FIELD_custom_data = New Dictionary(Of String, String)() From {{"order_type", "scheduled order"}},
             .day_scheduled_for_YYMMDD = "2017-12-20",
             .local_time_window_end = 39000,
             .local_time_window_end_2 = 46200,