using System;

public class Program

{

    public class klasa

    {

        public DateTime SigningTime {get;set;}

    }

    public static void Main()

    {

        var xmlstr = "<klasa><SigningTime>2025-04-03T23:56:50Z</SigningTime></klasa>";

        System.Xml.Serialization.XmlSerializer xmlSerializer = new System.Xml.Serialization.XmlSerializer(typeof(klasa));

        var result = (klasa)xmlSerializer.Deserialize(new System.IO.StringReader(xmlstr));

        Console.WriteLine( "Data odczytana: {0:yyyy-MM-dd HH:mm:ss.fff} {1}",result.SigningTime, result.SigningTime.Kind);

        var data2=result.SigningTime.ToLocalTime();

        Console.WriteLine( "Data odczytana: {0:yyyy-MM-dd HH:mm:ss.fff} {1}",data2,data2.Kind);

        var data3=result.SigningTime.ToUniversalTime();

        Console.WriteLine( "Data odczytana: {0:yyyy-MM-dd HH:mm:ss.fff} {1}",data3,data3.Kind);

    }

}