bug fix from my last bug fix :(

DtoImporterService/BookImporter.cs

@@ -120,7 +120,7 @@ namespace DtoImporterService
 
 			book.UpdateBookDetails(item.IsAbridged, item.DatePublished);
 
-			if (!string.IsNullOrWhiteSpace(item.PdfUrl.ToString()))
+			if (item.PdfUrl is not null)
 				book.AddSupplementDownloadUrl(item.PdfUrl.ToString());
 
 			return book;

LibationLauncher/LibationLauncher.csproj

@@ -13,7 +13,7 @@
     <!-- <PublishSingleFile>true</PublishSingleFile> -->
     <RuntimeIdentifier>win-x64</RuntimeIdentifier>
 
-    <Version>5.5.4.1</Version>
+    <Version>5.5.5.1</Version>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">