using System;

using Newtonsoft.Json;      

class Program

{

    static void Main(string[] args)

    {

        var json = "{\"MyDateTime\": \"0001-01-01T00:00:00+01:00\"}";

        var newtonDeserialized = JsonConvert.DeserializeObject<Class>(json);

​

        //Bad things happen here.

        var systemDeserialized =  System.Text.Json.JsonSerializer.Deserialize<Class>(json);

        Console.WriteLine(newtonDeserialized.MyDateTime);

        Console.WriteLine(systemDeserialized.MyDateTime);

    }

}

​

class Class

{

    public DateTime MyDateTime {get; set;}

}

​