diff --git a/EnvelopeGenerator.ReceiverUI/EnvelopeGenerator.ReceiverUI.csproj b/EnvelopeGenerator.ReceiverUI/EnvelopeGenerator.ReceiverUI.csproj
index fbdaa2e6..9f4ee25e 100644
--- a/EnvelopeGenerator.ReceiverUI/EnvelopeGenerator.ReceiverUI.csproj
+++ b/EnvelopeGenerator.ReceiverUI/EnvelopeGenerator.ReceiverUI.csproj
@@ -41,6 +41,9 @@
   <ItemGroup>
     <Folder Include="Properties\PublishProfiles\" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\EnvelopeGenerator.Application\EnvelopeGenerator.Application.csproj" />
+  </ItemGroup>
   <ItemGroup>
     <Content Update="wwwroot\docs\privacy-policy.en-US.html">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
diff --git a/EnvelopeGenerator.ReceiverUI/Models/AnnotationDto.cs b/EnvelopeGenerator.ReceiverUI/Models/AnnotationDto.cs
deleted file mode 100644
index ced9c039..00000000
--- a/EnvelopeGenerator.ReceiverUI/Models/AnnotationDto.cs
+++ /dev/null
@@ -1,32 +0,0 @@
-namespace EnvelopeGenerator.ReceiverUI.Models;
-
-/// <summary>
-/// Represents a pre-assigned signature annotation position on a specific page.
-/// <br/><br/>
-/// <b>Coordinate unit (X, Y):</b> Inches (GdPicture14 native unit),
-/// origin at the <b>top-left</b> corner of the page, both axes increase downward/rightward.
-/// <br/><br/>
-/// <b>Conversion to DevExpress:</b> Multiply by 100 (DX uses 1/100 inch).
-/// Convert: <c>xDX = xInches * 100.0</c>
-/// <br/>
-/// <b>Conversion to PDF Points:</b> Multiply by 72 (1 inch = 72 points).
-/// Convert: <c>xPt = xInches * 72.0</c>
-/// <br/>
-/// <b>Y-axis for PDF (bottom-left origin):</b> Flip required for iText7.
-/// Convert: <c>yPt = (pageHeightInches - yInches - elemHeightInches) * 72.0</c>
-/// </summary>
-[Obsolete("Use SignatureDto with SignatureService.")]
-public record AnnotationDto
-{
-    /// <summary>Unique identifier of the annotation.</summary>
-    public long Id { get; init; }
-
-    /// <summary>1-based page number within the document.</summary>
-    public int Page { get; init; }
-
-    /// <summary>Horizontal position in INCHES from the left edge of the page.</summary>
-    public double X { get; init; }
-
-    /// <summary>Vertical position in INCHES from the top edge of the page.</summary>
-    public double Y { get; init; }
-}
diff --git a/EnvelopeGenerator.ReceiverUI/Pages/Example/ReportViewer.razor b/EnvelopeGenerator.ReceiverUI/Pages/Example/ReportViewer.razor
index 6e5f275e..42bfc0d7 100644
--- a/EnvelopeGenerator.ReceiverUI/Pages/Example/ReportViewer.razor
+++ b/EnvelopeGenerator.ReceiverUI/Pages/Example/ReportViewer.razor
@@ -6,6 +6,7 @@
 @using DevExpress.Utils
 @using DevExpress.XtraPrinting
 @using DevExpress.XtraPrinting.Drawing
+@using EnvelopeGenerator.Application.Common.Dto
 @using Microsoft.JSInterop
 @using XtraReport = DevExpress.XtraReports.UI.XtraReport
 @using BottomMarginBand = DevExpress.XtraReports.UI.BottomMarginBand
@@ -301,7 +302,10 @@ Shown="OnPopupShownAsync">
     bool IsLoggingOut;
 
     IReadOnlyList<AnnotationDto> _annotations = [];
-    IEnumerable<int> AnnotationPages => _annotations.Select(a => a.Page).Distinct().OrderBy(p => p);
+    IEnumerable<int> AnnotationPages => _annotations
+    .Select(a => a.Page ?? throw new InvalidOperationException($"Annotation page is missing for annotation ID {a.Id}. Annotation details: X={a.X}, Y={a.Y}"))
+    .Distinct()
+    .OrderBy(p => p);
     EnvelopeReceiverDto? _envelopeReceiver;
     record SignatureCapture(string DataUrl, string FullName, string Position, string Place);
     SignatureCapture? _capturedSignature;
diff --git a/EnvelopeGenerator.ReceiverUI/Services/AnnotationService.cs b/EnvelopeGenerator.ReceiverUI/Services/AnnotationService.cs
index ead7437c..74bb3960 100644
--- a/EnvelopeGenerator.ReceiverUI/Services/AnnotationService.cs
+++ b/EnvelopeGenerator.ReceiverUI/Services/AnnotationService.cs
@@ -1,5 +1,6 @@
 using System.Net.Http.Json;
 using System.Text.Json;
+using EnvelopeGenerator.Application.Common.Dto;
 using EnvelopeGenerator.ReceiverUI.Models;
 using EnvelopeGenerator.ReceiverUI.Options;
 using Microsoft.Extensions.Options;