Problem identifying improvements between different versions

When you read the online documentation for a class, how do you know from which version it was implemented? For example, the RemoveFiles method of the session class is not recognized with WinScpNet.dll version 1.8.3.11829, but it is recognized with version 1.8.3.11933.

Those are just different builds of the same version. They should not differ whatsoever. Additionally, the Session.RemoveFiles exists since the very first version of the .NET assembly and was never changed, let only removed. Your problem must be different than what you think. Give us more details.