First, it is essential to clarify a common misconception: is not a major release like 4.5 or 4.8. Instead, it is a specific build number (update) of .NET Framework 4.0. The base version of .NET Framework 4.0 was released in April 2010, and build 4.0.3019 corresponds to an early update (often included in Windows Update KB2183461 or similar hotfixes).
Which would you like next?