When do we need to use System.AppContext?

Question

Seems AppContext only has a property called BaseDirectory. But Environment class seems to have much more properties and methods.

So is AppContext being replaced by Environment class now?

Answer 1

AppContext has been introduced with .NET 4.6 thus it won't be replaced.

MSDN says:

AppContext is a new compatibility feature that enables library writers to provide a uniform opt-out mechanism for new functionality for their users. It established a loosley-coupled contract between components in order to communicate an opt-out request. This capability is typically important when a change is made to existing functionality. Conversely, there is already an implicit opt-in for new functionality.

With AppContext, libraries define and expose compatibility switches, while code that depends on them can set those switches, to affect the library behavior. By default libraries provide the new functionality and only alter it (e.g. provide the old behavior) if the switch is set.

In summary, it provides functionality to deal with multiple versions of the same dll.

Code example is within the provided link.