public event PivotLayoutUpgradeEventHandler LayoutUpgrade

Public Event LayoutUpgrade As PivotLayoutUpgradeEventHandler

using DevExpress.Xpf.PivotGrid;
using System.IO;
using System.Windows;

namespace HowToSaveAndRestoreLayoutFromStream {
    public partial class MainWindow : Window {
        // Create a MemoryStream instance.
        System.IO.Stream LayoutStream = new System.IO.MemoryStream();
        public MainWindow() {
            InitializeComponent();
            PivotGridGroup group = pivotGridControlNew.Groups.Add(fieldYear, fieldMonth);         
        }
        private void buttonSave_Click(object sender, RoutedEventArgs e) {
            // Save the layout to a stream.
            pivotGridControlOld.SaveLayoutToStream(LayoutStream);
        }
        private void buttonLoad_Click(object sender, RoutedEventArgs e) {
            LayoutStream.Position = 0;
            LayoutStream.Seek(0, SeekOrigin.Begin);
            // Load the layout from the stream.
            pivotGridControlNew.RestoreLayoutFromStream(LayoutStream);
        }
        private void pivotGridControlNew_LayoutUpgrade(object sender, PivotLayoutUpgradeEventArgs e) {
            if (e.PreviousVersion == "1.0") {
                var newField = new PivotGridField() {
                    DataBinding = new DataSourceColumnBinding("Quantity"),
                    Caption = "Quantity",
                    Name = "fieldQuantity",
                    Area = FieldArea.DataArea
                };
                pivotGridControlNew.Fields.Add(newField);
            };
        }
    }
}

Imports DevExpress.Xpf.PivotGrid
Imports System.IO
Imports System.Windows

Namespace HowToSaveAndRestoreLayoutFromStream

    Public Partial Class MainWindow
        Inherits Window

        ' Create a MemoryStream instance.
        Private LayoutStream As Stream = New MemoryStream()

        Public Sub New()
            Me.InitializeComponent()
            Dim group As PivotGridGroup = Me.pivotGridControlNew.Groups.Add(Me.fieldYear, Me.fieldMonth)
        End Sub

        Private Sub buttonSave_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
            ' Save the layout to a stream.
            Me.pivotGridControlOld.SaveLayoutToStream(LayoutStream)
        End Sub

        Private Sub buttonLoad_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
            LayoutStream.Position = 0
            LayoutStream.Seek(0, SeekOrigin.Begin)
            ' Load the layout from the stream.
            Me.pivotGridControlNew.RestoreLayoutFromStream(LayoutStream)
        End Sub

        Private Sub pivotGridControlNew_LayoutUpgrade(ByVal sender As Object, ByVal e As PivotLayoutUpgradeEventArgs)
            If Equals(e.PreviousVersion, "1.0") Then
                Dim newField = New PivotGridField() With {.DataBinding = New DataSourceColumnBinding("Quantity"), .Caption = "Quantity", .Name = "fieldQuantity", .Area = FieldArea.DataArea}
                Me.pivotGridControlNew.Fields.Add(newField)
            End If
        End Sub
    End Class
End Namespace

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition />
        <RowDefinition />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <dxpg:PivotGridControl Name="pivotGridControlOld" 
                           DataSource="{Binding Path=Data, Source={StaticResource TypedSimpleSource}}"
                           DataProcessingEngine="Optimized"
                           dx:DXSerializer.LayoutVersion="1.0">
        <dxpg:PivotGridControl.Fields>
            <dxpg:PivotGridField Name="fieldCategory" Caption="Category" Area="RowArea">
                <dxpg:PivotGridField.DataBinding>
                    <dxpg:DataSourceColumnBinding ColumnName="CategoryName"/>
                </dxpg:PivotGridField.DataBinding>
            </dxpg:PivotGridField>
            <dxpg:PivotGridField Name="fieldExtendedPrice" Area="DataArea" CellFormat="c0">
                <dxpg:PivotGridField.DataBinding>
                    <dxpg:DataSourceColumnBinding ColumnName="Extended Price"/>
                </dxpg:PivotGridField.DataBinding>
            </dxpg:PivotGridField>
        </dxpg:PivotGridControl.Fields>
    </dxpg:PivotGridControl>
    <dxpg:PivotGridControl Grid.Row="1" Name="pivotGridControlNew" 
                           DataSource="{Binding Path=Data, Source={StaticResource TypedSimpleSource}}" 
                           DataProcessingEngine="Optimized"
                           dx:DXSerializer.LayoutVersion="2.0"
                           dxpg:PivotSerializationOptions.AddNewGroups="True"
                           dxpg:PivotSerializationOptions.AddNewFields="True"
                           dxpg:PivotSerializationOptions.RemoveOldFields="False"
                           LayoutUpgrade="pivotGridControlNew_LayoutUpgrade">
        <dxpg:PivotGridControl.Fields>
        <dxpg:PivotGridField Name="fieldYear" Area="ColumnArea" Caption="Year"
                             Group="{Binding ElementName=group}">
            <dxpg:PivotGridField.DataBinding>
                <dxpg:DataSourceColumnBinding ColumnName="OrderDate" GroupInterval="DateYear"/>
            </dxpg:PivotGridField.DataBinding>
        </dxpg:PivotGridField>
        <dxpg:PivotGridField Name="fieldMonth" Area="ColumnArea" Caption="Month"
                             Group="{Binding ElementName=group}">
        <dxpg:PivotGridField.DataBinding>
            <dxpg:DataSourceColumnBinding ColumnName="OrderDate" GroupInterval="DateMonth"/>
        </dxpg:PivotGridField.DataBinding>
        </dxpg:PivotGridField>
        </dxpg:PivotGridControl.Fields>
    </dxpg:PivotGridControl>
    <StackPanel Grid.Row="2" Orientation="Horizontal" >
        <Button Name="buttonSave" Content="Save" Padding="8, 4, 8, 4" 
                Margin="4" Click="buttonSave_Click" ></Button>
        <Button Name="buttonLoad" Content="Load" Padding="8, 4, 8, 4" 
                Margin="4" Click="buttonLoad_Click"></Button>
    </StackPanel>
</Grid>