namespace DotNetNuke.Services.Upgrade.Internals
{
    internal class InstallControllerImpl : IInstallController
...
public bool IsValidSqlServerVersion(string connectionString)
{
	//todo: check if we can use globals.DatabaseEngineVersion instead

	bool isValidVersion = false;
	var sqlConnection = new SqlConnection(connectionString);
	try
	{
		sqlConnection.Open();

		string serverVersion = sqlConnection.ServerVersion;
		if (serverVersion != null)
		{
			string[] serverVersionDetails = serverVersion.Split(new[] {"."}, StringSplitOptions.None);

			int versionNumber = int.Parse(serverVersionDetails[0]);

			switch (versionNumber)
			{
				case 8:
					//sql 2000
				case 9:
					//sql 2005
					break;
				case 10:
					//sql 2008
				case 11:
					//sql 2010
				case 12:
					//sql 2012
					isValidVersion = true;
					break;
				default:
					//covers unknown versions and later releases
					isValidVersion = true;
					break;
			}
		}
	}
	catch (Exception)
	{
		//cannot connect with the details
		isValidVersion = false;
	}
	finally
	{
		sqlConnection.Close();
	}
	return isValidVersion;
}