<PackageReference Include="System.Configuration.ConfigurationManager" Version="4.5.0-preview1-26216-02" />

ConfigurationSettings

public sealed class ConfigurationSettings
using System.Collections.Specialized; namespace System.Configuration { public sealed class ConfigurationSettings { [Obsolete("This method is obsolete, it has been replaced by System.Configuration!System.Configuration.ConfigurationManager.AppSettings")] public static NameValueCollection AppSettings { get { return ConfigurationManager.AppSettings; } } [Obsolete("This method is obsolete, it has been replaced by System.Configuration!System.Configuration.ConfigurationManager.GetSection")] public static object GetConfig(string sectionName) { return ConfigurationManager.GetSection(sectionName); } } }