DbUp - NullReferenceException when using SqlTableJournal

Question

I get the following error when using a SqlTableJournal or when using a custom Journal that implements TableJournal.

If I change the DeployChanges.To... code and remove the .JournalTo(journal) line, the problem goes away.

My main goals is to add more columns to the SchemaVersions table, by adding what release version a script was applied on. If there's an easier way to do this please can someone let me know.

Upgrade failed due to an unexpected exception:
System.NullReferenceException: Object reference not set to an instance of an object.
   at DbUp.Engine.Transactions.DatabaseConnectionManager.ExecuteCommandsWithManagedConnection[T](Func`2 actionWithResult)
   at DbUp.Engine.UpgradeEngine.GetScriptsToExecuteInsideOperation()
   at DbUp.Engine.UpgradeEngine.PerformUpgrade()
System.NullReferenceException: Object reference not set to an instance of an object.
   at DbUp.Engine.Transactions.DatabaseConnectionManager.ExecuteCommandsWithManagedConnection[T](Func`2 actionWithResult)
   at DbUp.Engine.UpgradeEngine.GetScriptsToExecuteInsideOperation()
   at DbUp.Engine.UpgradeEngine.PerformUpgrade()

using DbUp.Engine;
using DbUp.Engine.Output;
using DbUp.SqlServer;
using System.Data.SqlClient;

namespace SQLScriptDeploymentTool
{
    internal class Program
    {
        private static string ConnectionString => "Data Source=(local);Initial Catalog=db;User Id=dbuser;password=dbpass;";

        static void Main()
        {
            var connectionString = BuildConnectionString("(local)", "db", "dbuser", "dbpass");
            var journal = GenerateJournal(ConnectionString);

            var version = string.Empty;
            DatabaseUpgradeResult result;
            if (version != string.Empty)
            {
                result = PerformRollback(journal, ConnectionString, version);
            }
            else
            {
                result = PerformRollforward(journal, ConnectionString, version);
            }

            if (!result.Successful)
            {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine(result.Error);
                Console.ResetColor();
                Console.ReadLine();
                return;
            }

            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Success!");
            Console.ResetColor();
            Console.ReadLine();
            return;
        }

        private static DatabaseUpgradeResult PerformRollback(SqlTableJournal journal, string connectionString, string version)
        {
            var sqlScripts = RetrieveScriptstoRollback(version);

            var upgrader =
                DeployChanges.To
                    .SqlDatabase(connectionString)
                    .JournalTo(journal)
                    .WithScripts(sqlScripts)
                    .LogToConsole()
                    .Build();

            return upgrader.PerformUpgrade();
        }

        private static DatabaseUpgradeResult PerformRollforward(SqlTableJournal journal, string connectionString, string version)
        {
            var upgrader =
                DeployChanges.To
                    .SqlDatabase(connectionString)
                    .JournalTo(journal)
                    .WithScriptsFromFileSystem("C:/Projects/P-Platform/MppGlobal.BuildResources/SqlScripts/PostSSDT/P-Core/228.0/Rollforward")
                    .LogToConsole()
                    .Build();

            return upgrader.PerformUpgrade();
        }

        private static SqlTableJournal GenerateJournal(string connectionString)
        {
            var connectionManager = new SqlConnectionManager(connectionString);
            var logger = new ConsoleUpgradeLog();
            return new SqlTableJournal(() => connectionManager, () => logger, "dbo", "DeploymentScriptLog");
        }

        private static SqlScript[] RetrieveScriptstoRollback(string version)
        {
            IList<SqlScript> scriptsToRollback = new List<SqlScript>();
            SqlConnection connection = new(ConnectionString);
            connection.Open();

            var sql = $"SELECT [ScriptName], [Applied] FROM [dbo].[SchemaVersions] WHERE [Applied] > '{ConvertVersionToDateTime(version)}'";
            SqlCommand command = new(sql, connection);
            SqlDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                scriptsToRollback.Add(new SqlScript(reader.GetString(0), ""));
            }

            return scriptsToRollback.ToArray();
        }

        private static string BuildConnectionString(string server, string database, string username, string password)
        {
            var conn = new SqlConnectionStringBuilder
            {
                DataSource = server,
                InitialCatalog = database
            };

            if (!String.IsNullOrEmpty(username))
            {
                conn.UserID = username;
                conn.Password = password;
                conn.IntegratedSecurity = false;
            }
            else
            {
                conn.IntegratedSecurity = true;
            }

            return conn.ToString();
        }

        private static string ConvertVersionToDateTime(string version)
        {
            var year = int.Parse(version[0..4]);
            var month = int.Parse(version[4..6]);
            var day = int.Parse(version[6..8].ToString());

            return $"{year}-{month}-{day}";
        }
    }
}