using System.Text.Json;
 
public class Test
{
	public static void Main()
	{
		var contractJson = JsonSerializer.Serialize(new Contract { Letters = Letters.A });
		var contractV2Json = JsonSerializer.Serialize(new ContractV2 { Letters = EvolvedLetters.A });
		Console.WriteLine(contractJson);
		Console.WriteLine(contractV2Json);
	}
}
 
 
public class Contract
{
    public Letters Letters { get; set; }
}
 
public class ContractV2
{
    public EvolvedLetters Letters { get; set; }
}
 
public enum Letters
{
    A = 1,
    B = 2,
    C = 3,
}
 
public enum EvolvedLetters
{
    A = 1,
    B = 2,
    C = 3,
    D = 4,
}

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