Chapter 1, Page 9
The names to describe the different support length of .NET changed. In the book you can read about Current and Long Term Support (LTS) monikers. The new name for Current is now Standard Term Support (STS). STS is supported for 18 months, and LTS for 36 months (the lenght didn't change).
Chapter 15, Dependency Injection and Configuration
.NET 7 includes the HostApplicationBuilder which simplifies creating the DI container. Instead of using Host.ConfigureDefaultServices, the HostApplicationBuilder is used to configure the DI container. The HostApplicationBuilder is used removes the need to pass delegates to configure services, app configuration, and logging.
Chapter 12, Reflection, Metadata, and Source Generators, Page 328
With .NET 7, the source generator sample makes use of raw string literals. Thnis makes the code more readable, and the code is easier to maintain.
See the Readme for more information.
Chapter 19, Networking, page 545
The HttpServer code sample is changed to use C# 11 raw string literals.
Chapter 13, Managed and unmanaged Memory, Page 368
With .NET 7, the LibraryImport attribute can be used instead of DllImport. This new attribute makes use of a source generator.
See PInvokeSampleLib in More Samples. This Readme gives information on changes needed.
Chapter 25, "Services", Page 715
.NET 6 added Minimal APIs. .NET 7 added TypedResults. Minimal APIs are a new feature in .NET 6 that allows you to create a web API without controllers. .NET 7 adds typed results (the TypedResults class) which adds information to the OpenAPI document.