Framework V 4 < SIMPLE >
Framework 4.0 is arguably the most important release in .NET history before the jump to .NET Core. It introduced the Task object, which is the bedrock of modern C# async/await programming (introduced later in v4.5). Without Framework 4.0's TPL, modern scalable .NET applications would not exist.
Released in April 2010, .NET Framework 4.0 represented a massive evolutionary leap for Microsoft’s development platform. Coming three years after version 3.5, it was not merely an incremental update; it was a foundational rewrite that introduced paradigms that define modern .NET development today. framework v 4