using System;

using System.Linq;

using System.Reflection;

using Newtonsoft.Json;

using Newtonsoft.Json.Serialization;

public class Program

{

    public static void Main()

    {

        var foo = new Foo { Id = 123, Age = 23 };

        var settings = new JsonSerializerSettings

        {

            ContractResolver = new ExcludeObsoletePropertiesResolver()

        };

        var json = JsonConvert.SerializeObject(foo, settings);

        Console.WriteLine(json);

    }

}

​

public class ExcludeObsoletePropertiesResolver : DefaultContractResolver

{

    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)

    {

        JsonProperty prop = base.CreateProperty(member, memberSerialization);

        if (prop.AttributeProvider.GetAttributes(true).OfType<ObsoleteAttribute>().Any())

        {

            prop.ShouldSerialize = obj => false;

        }

        return prop;

    }

}

​

public class Foo

{

    public int Id { get; set; }

​

    [Obsolete]

    public int Age { get; set; }

}

​