diff --git a/CliFx.Demo/CliFx.Demo.csproj b/CliFx.Demo/CliFx.Demo.csproj
index bcd69f3..ad30973 100644
--- a/CliFx.Demo/CliFx.Demo.csproj
+++ b/CliFx.Demo/CliFx.Demo.csproj
@@ -7,7 +7,6 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/CliFx.Demo/Domain/Book.cs b/CliFx.Demo/Domain/Book.cs
index 24266bc..47e23f1 100644
--- a/CliFx.Demo/Domain/Book.cs
+++ b/CliFx.Demo/Domain/Book.cs
@@ -2,21 +2,4 @@
 
 namespace CliFx.Demo.Domain;
 
-public class Book
-{
-    public string Title { get; }
-
-    public string Author { get; }
-
-    public DateTimeOffset Published { get; }
-
-    public Isbn Isbn { get; }
-
-    public Book(string title, string author, DateTimeOffset published, Isbn isbn)
-    {
-        Title = title;
-        Author = author;
-        Published = published;
-        Isbn = isbn;
-    }
-}
\ No newline at end of file
+public record Book(string Title, string Author, DateTimeOffset Published, Isbn Isbn);
\ No newline at end of file
diff --git a/CliFx.Demo/Domain/Isbn.cs b/CliFx.Demo/Domain/Isbn.cs
index 8fdbdfb..ff2f0fc 100644
--- a/CliFx.Demo/Domain/Isbn.cs
+++ b/CliFx.Demo/Domain/Isbn.cs
@@ -2,32 +2,13 @@
 
 namespace CliFx.Demo.Domain;
 
-public partial class Isbn
+public partial record Isbn(int EanPrefix, int RegistrationGroup, int Registrant, int Publication, int CheckDigit)
 {
-    public int EanPrefix { get; }
-
-    public int RegistrationGroup { get; }
-
-    public int Registrant { get; }
-
-    public int Publication { get; }
-
-    public int CheckDigit { get; }
-
-    public Isbn(int eanPrefix, int registrationGroup, int registrant, int publication, int checkDigit)
-    {
-        EanPrefix = eanPrefix;
-        RegistrationGroup = registrationGroup;
-        Registrant = registrant;
-        Publication = publication;
-        CheckDigit = checkDigit;
-    }
-
     public override string ToString() =>
         $"{EanPrefix:000}-{RegistrationGroup:00}-{Registrant:00000}-{Publication:00}-{CheckDigit:0}";
 }
 
-public partial class Isbn
+public partial record Isbn
 {
     public static Isbn Parse(string value, IFormatProvider formatProvider)
     {
diff --git a/CliFx.Demo/Domain/Library.cs b/CliFx.Demo/Domain/Library.cs
index 96137a9..8032e5d 100644
--- a/CliFx.Demo/Domain/Library.cs
+++ b/CliFx.Demo/Domain/Library.cs
@@ -4,15 +4,8 @@ using System.Linq;
 
 namespace CliFx.Demo.Domain;
 
-public partial class Library
+public partial record Library(IReadOnlyList<Book> Books)
 {
-    public IReadOnlyList<Book> Books { get; }
-
-    public Library(IReadOnlyList<Book> books)
-    {
-        Books = books;
-    }
-
     public Library WithBook(Book book)
     {
         var books = Books.ToList();
@@ -29,7 +22,7 @@ public partial class Library
     }
 }
 
-public partial class Library
+public partial record Library
 {
     public static Library Empty { get; } = new(Array.Empty<Book>());
 }
\ No newline at end of file
diff --git a/CliFx.Demo/Domain/LibraryProvider.cs b/CliFx.Demo/Domain/LibraryProvider.cs
index 3ebc04c..478c368 100644
--- a/CliFx.Demo/Domain/LibraryProvider.cs
+++ b/CliFx.Demo/Domain/LibraryProvider.cs
@@ -1,6 +1,6 @@
 using System.IO;
 using System.Linq;
-using Newtonsoft.Json;
+using System.Text.Json;
 
 namespace CliFx.Demo.Domain;
 
@@ -10,7 +10,7 @@ public class LibraryProvider
 
     private void StoreLibrary(Library library)
     {
-        var data = JsonConvert.SerializeObject(library);
+        var data = JsonSerializer.Serialize(library);
         File.WriteAllText(StorageFilePath, data);
     }
 
@@ -21,7 +21,7 @@ public class LibraryProvider
 
         var data = File.ReadAllText(StorageFilePath);
 
-        return JsonConvert.DeserializeObject<Library>(data) ?? Library.Empty;
+        return JsonSerializer.Deserialize<Library>(data) ?? Library.Empty;
     }
 
     public Book? TryGetBook(string title) => GetLibrary().Books.FirstOrDefault(b => b.Title == title);
diff --git a/Readme.md b/Readme.md
index feaaf1a..3917e98 100644
--- a/Readme.md
+++ b/Readme.md
@@ -23,7 +23,7 @@ By using this project or its source code, for any purpose and in any shape or fo
 - You **support Ukraine's territorial integrity, including its claims over temporarily occupied territories of Crimea and Donbas**
 - You **reject false narratives perpetuated by Russian state propaganda**
 
-To learn more about the war and how you can help, [click here](https://tyrrrz.me). Glory to Ukraine! 🇺🇦
+To learn more about the war and how you can help, [click here](https://tyrrrz.me/ukraine). Glory to Ukraine! 🇺🇦
 
 ## Install