diff --git a/DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj b/DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj
index c98f66c..8497178 100644
--- a/DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj
+++ b/DiscordChatExporter.Cli/DiscordChatExporter.Cli.csproj
@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="CliFx" Version="2.0.1" />
+    <PackageReference Include="CliFx" Version="2.0.3" />
     <PackageReference Include="Spectre.Console" Version="0.38.0" />
     <PackageReference Include="Gress" Version="1.2.0" />
     <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
diff --git a/DiscordChatExporter.Core/DiscordChatExporter.Core.csproj b/DiscordChatExporter.Core/DiscordChatExporter.Core.csproj
index b3b8fc8..335d47f 100644
--- a/DiscordChatExporter.Core/DiscordChatExporter.Core.csproj
+++ b/DiscordChatExporter.Core/DiscordChatExporter.Core.csproj
@@ -7,7 +7,7 @@
   <ItemGroup>
     <PackageReference Include="JsonExtensions" Version="1.0.1" />
     <PackageReference Include="MiniRazor.CodeGen" Version="2.1.2" />
-    <PackageReference Include="Polly" Version="7.2.1" />
+    <PackageReference Include="Polly" Version="7.2.2" />
     <PackageReference Include="Tyrrrz.Extensions" Version="1.6.5" />
   </ItemGroup>
 
diff --git a/DiscordChatExporter.Gui/App.xaml b/DiscordChatExporter.Gui/App.xaml
index b5a501e..e2f65d1 100644
--- a/DiscordChatExporter.Gui/App.xaml
+++ b/DiscordChatExporter.Gui/App.xaml
@@ -41,7 +41,7 @@
             <Style BasedOn="{StaticResource MaterialDesignLinearProgressBar}" TargetType="{x:Type ProgressBar}">
                 <Setter Property="BorderThickness" Value="0" />
                 <Setter Property="Background" Value="Transparent" />
-                <Setter Property="Foreground" Value="{DynamicResource SecondaryAccentBrush}" />
+                <Setter Property="Foreground" Value="{DynamicResource SecondaryHueMidBrush}" />
                 <Setter Property="Height" Value="2" />
                 <Setter Property="Maximum" Value="1" />
                 <Setter Property="Minimum" Value="0" />
@@ -68,7 +68,7 @@
                             <Setter Property="Height" Value="36" />
                             <Setter Property="Margin" Value="8,-10,-8,-10" />
                             <Setter Property="Padding" Value="8" />
-                            <Setter Property="Foreground" Value="{DynamicResource SecondaryAccentBrush}" />
+                            <Setter Property="Foreground" Value="{DynamicResource SecondaryHueMidBrush}" />
                             <Setter Property="materialDesign:RippleAssist.Feedback" Value="{DynamicResource MaterialDesignSnackbarRipple}" />
                         </Style>
                     </Setter.Value>
@@ -122,7 +122,7 @@
                                         IsChecked="{Binding Path=IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"
                                         IsTabStop="False"
                                         Opacity=".87"
-                                        Style="{StaticResource MaterialDesignExpanderDownHeaderStyle}"
+                                        Style="{StaticResource MaterialDesignExpanderToggleButton}"
                                         TextElement.FontSize="15" />
                                     <Border
                                         Name="ContentSite"
@@ -152,7 +152,7 @@
                                     <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Right" />
                                     <Setter TargetName="ContentPanel" Property="Orientation" Value="Horizontal" />
                                     <Setter TargetName="ContentPanel" Property="Height" Value="Auto" />
-                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderRightHeaderStyle}" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignVerticalHeaderStyle}" />
                                 </Trigger>
 
                                 <Trigger Property="ExpandDirection" Value="Left">
@@ -160,7 +160,7 @@
                                     <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Left" />
                                     <Setter TargetName="ContentPanel" Property="Orientation" Value="Horizontal" />
                                     <Setter TargetName="ContentPanel" Property="Height" Value="Auto" />
-                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderLeftHeaderStyle}" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignVerticalHeaderStyle}" />
                                 </Trigger>
 
                                 <Trigger Property="ExpandDirection" Value="Up">
@@ -168,7 +168,7 @@
                                     <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Top" />
                                     <Setter TargetName="ContentPanel" Property="Orientation" Value="Vertical" />
                                     <Setter TargetName="ContentPanel" Property="Width" Value="Auto" />
-                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderUpHeaderStyle}" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignHorizontalHeaderStyle}" />
                                 </Trigger>
 
                                 <Trigger Property="ExpandDirection" Value="Down">
@@ -176,7 +176,7 @@
                                     <Setter TargetName="ContentSite" Property="DockPanel.Dock" Value="Bottom" />
                                     <Setter TargetName="ContentPanel" Property="Orientation" Value="Vertical" />
                                     <Setter TargetName="ContentPanel" Property="Width" Value="Auto" />
-                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignExpanderDownHeaderStyle}" />
+                                    <Setter TargetName="HeaderSite" Property="Style" Value="{StaticResource MaterialDesignHorizontalHeaderStyle}" />
                                 </Trigger>
                             </ControlTemplate.Triggers>
                         </ControlTemplate>
diff --git a/DiscordChatExporter.Gui/DiscordChatExporter.Gui.csproj b/DiscordChatExporter.Gui/DiscordChatExporter.Gui.csproj
index 2b9251e..0a13e36 100644
--- a/DiscordChatExporter.Gui/DiscordChatExporter.Gui.csproj
+++ b/DiscordChatExporter.Gui/DiscordChatExporter.Gui.csproj
@@ -13,8 +13,8 @@
 
   <ItemGroup>
     <PackageReference Include="Gress" Version="1.2.0" />
-    <PackageReference Include="MaterialDesignColors" Version="1.2.2" />
-    <PackageReference Include="MaterialDesignThemes" Version="3.0.1" />
+    <PackageReference Include="MaterialDesignColors" Version="2.0.0" />
+    <PackageReference Include="MaterialDesignThemes" Version="4.0.0" />
     <PackageReference Include="Microsoft.Xaml.Behaviors.Wpf" Version="1.1.31" />
     <PackageReference Include="Ookii.Dialogs.Wpf" Version="3.1.0" />
     <PackageReference Include="Onova" Version="2.6.2" />
diff --git a/DiscordChatExporter.Gui/ViewModels/Framework/DialogManager.cs b/DiscordChatExporter.Gui/ViewModels/Framework/DialogManager.cs
index 69f2abc..3af7be6 100644
--- a/DiscordChatExporter.Gui/ViewModels/Framework/DialogManager.cs
+++ b/DiscordChatExporter.Gui/ViewModels/Framework/DialogManager.cs
@@ -17,7 +17,7 @@ namespace DiscordChatExporter.Gui.ViewModels.Framework
             _viewManager = viewManager;
         }
 
-        public async ValueTask<T> ShowDialogAsync<T>(DialogScreen<T> dialogScreen)
+        public async ValueTask<T?> ShowDialogAsync<T>(DialogScreen<T> dialogScreen)
         {
             var view = _viewManager.CreateAndBindViewForModelIfNecessary(dialogScreen);
 
diff --git a/DiscordChatExporter.Gui/ViewModels/Framework/DialogScreen.cs b/DiscordChatExporter.Gui/ViewModels/Framework/DialogScreen.cs
index 05f0cf1..05e74b4 100644
--- a/DiscordChatExporter.Gui/ViewModels/Framework/DialogScreen.cs
+++ b/DiscordChatExporter.Gui/ViewModels/Framework/DialogScreen.cs
@@ -5,14 +5,13 @@ namespace DiscordChatExporter.Gui.ViewModels.Framework
 {
     public abstract class DialogScreen<T> : PropertyChangedBase
     {
-        // ReSharper disable once RedundantDefaultMemberInitializer
-        public T DialogResult { get; private set; } = default!;
+        public T? DialogResult { get; private set; }
 
         public event EventHandler? Closed;
 
-        public void Close(T dialogResult = default!)
+        public void Close(T dialogResult)
         {
-            DialogResult = dialogResult!;
+            DialogResult = dialogResult;
             Closed?.Invoke(this, EventArgs.Empty);
         }
     }