.NET Framework 3.5 Features:
Language Integrated Query (LINQ) for SQL, XML, Dataset, Object
p2p base class
Anonymous types with static type inference
Paging support for ADO.NET
ADO.NET synchronization API to synchronize local caches and server side data stores
Asynchronous network I/O API
Support for HTTP pipelining and syndication feeds.
New System.CodeDom namespace
.NET Framework 4.0 Features:
Common Language Runtime (CLR) Ã¢â¬â The following sections describe new features in security, parallel computing, performance and diagnostics, dynamic language runtime, and other CLR-related technologies
Base Class Libraries
Networking Ã¢â¬â Enhancements have been made that affect how integrated Windows authentication is handled by the HttpWebRequest, HttpListener, SmtpClient, SslStream, NegotiateStream, and related classes in the System.Net and related namespaces
Web Ã¢â¬â The following sections describe new features in ASP.NET core services, Web Forms, Dynamic Data, and Visual Web Developer.
Client Ã¢â¬â The following sections describe new features in Windows Presentation Foundation (WPF) and Managed Extensibility Framework (MEF).
Communications Ã¢â¬â Windows Communication Foundation (WCF) provides the new features and enhancements described in the following sections.
Workflow Ã¢â¬â Windows Workflow Foundation (WF) in .NET Framework 4.0 changes several development paradigms from earlier versions. Workflows are now easier to create, execute, and maintain.