The release of 3.5 was closely tied to , which introduced several "quality-of-life" improvements and deep integrations for web developers: What's New in ASP.NET 3.5? - CODE Magazine
is a pivotal version of Microsoft’s web development framework, released on November 19, 2007 . It was designed as an incremental, "additive" upgrade to ASP.NET 2.0, meaning it maintained the same core Common Language Runtime (CLR) 2.0 while introducing significant new libraries and features that fundamentally changed how developers wrote web applications. Core Advancements in ASP.NET 3.5 asp net 3.5