IPN Simulator returning invalid

[Keila91]

I've been trying to make sure a site ready for the updates coming June 1st, but every time I do a test with the IPN Simulator, it's returning invalid.  I know IPN messages are enabled. I've tried making the payment_date = NULL as some threads have suggested. The data being returned looks correct... The IPN Simulator is saying that the IPN was sent and handshake verified. The live site has been working because I periodically get emails when a purchase successfully goes through and I have received one in the last week. I'm not sure what could be wrong with my simulator usage? Something to do with the new security changes maybe? I'm using the script below:

<?php
class PaypalIPN
{
    /** @var bool Indicates if the sandbox endpoint is used. */
    private $use_sandbox = true;
    /** @var bool Indicates if the local certificates are used. */
    private $use_local_certs = true;
    /** Production Postback URL */
    const VERIFY_URI = 'https://ipnpb.paypal.com/cgi-bin/webscr';
    /** Sandbox Postback URL */
    const SANDBOX_VERIFY_URI = 'https://ipnpb.sandbox.paypal.com/cgi-bin/webscr';
    /** Response from PayPal indicating validation was successful */
    const VALID = 'VERIFIED';
    /** Response from PayPal indicating validation failed */
    const INVALID = 'INVALID';
    /**
     * Sets the IPN verification to sandbox mode (for use when testing,
     * should not be enabled in production).
     * @return void
     */
    public function useSandbox()
    {
        $this->use_sandbox = true;
    }
    /**
     * Sets curl to use php curl's built in certs (may be required in some
     * environments).
     * @return void
     */
    public function usePHPCerts()
    {
        $this->use_local_certs = false;
    }
    /**
     * Determine endpoint to post the verification data to.
     *
     * @return string
     */
    public function getPaypalUri()
    {
        if ($this->use_sandbox) {
            return self::SANDBOX_VERIFY_URI;
        } else {
            return self::VERIFY_URI;
        }
    }
    /**
     * Verification Function
     * Sends the incoming post data back to PayPal using the cURL library.
     *
     * @return bool
     * @throws Exception
     */
    public function verifyIPN()
    {
        if ( ! count($_POST)) {
            throw new Exception("Missing POST Data");
        }
        $raw_post_data = file_get_contents('php://input');
        $raw_post_array = explode('&', $raw_post_data);
        $myPost = array();
        foreach ($raw_post_array as $keyval) {
            $keyval = explode('=', $keyval);
            if (count($keyval) == 2) {
                // Since we do not want the plus in the datetime string to be encoded to a space, we manually encode it.
                if ($keyval[0] === 'payment_date') {
                    if (substr_count($keyval[1], '+') === 1) {
                        $keyval[1] = str_replace('+', '%2B', $keyval[1]);
                    }
                }
                $myPost[$keyval[0]] = urldecode($keyval[1]);
            }
        }
        // Build the body of the verification post request, adding the _notify-validate command.
        $req = 'cmd=_notify-validate';
        $get_magic_quotes_exists = false;
        if (function_exists('get_magic_quotes_gpc')) {
            $get_magic_quotes_exists = true;
        }
        foreach ($myPost as $key => $value) {
            if ($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
                $value = urlencode(stripslashes($value));
            } else {
                $value = urlencode($value);
            }
            $req .= "&$key=$value";
        }
        // Post the data back to PayPal, using curl. Throw exceptions if errors occur.
        $ch = curl_init($this->getPaypalUri());
        curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
        curl_setopt($ch, CURLOPT_SSLVERSION, 6);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
        // This is often required if the server is missing a global cert bundle, or is using an outdated one.
        if ($this->use_local_certs) {
            curl_setopt($ch, CURLOPT_CAINFO, __DIR__ . "/cert/cacert.pem");
        }
        curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'User-Agent: PHP-IPN-Verification-Script',
            'Connection: Close',
        ));
        $res = curl_exec($ch);
        if ( ! ($res)) {
            $errno = curl_errno($ch);
            $errstr = curl_error($ch);
            curl_close($ch);
            throw new Exception("cURL error: [$errno] $errstr");
        }
        $info = curl_getinfo($ch);
        $http_code = $info['http_code'];
        if ($http_code != 200) {
            throw new Exception("PayPal responded with http code $http_code");
        }
        curl_close($ch);
        // Check if PayPal verifies the IPN data, and if so, return true.
        if ($res == self::VALID) {
            return true;
        } else {
            return false;
        }
    }
}

<?php namespace Listener;
// Set this to true to use the sandbox endpoint during testing:
$enable_sandbox = true;
// Use this to specify all of the email addresses that you have attached to paypal:
$my_email_addresses = array("email", "email", "email");
// Set this to true to send a confirmation email:
$send_confirmation_email = true;
$confirmation_email_address = "email";
$from_email_address = "email>";
// Set this to true to save a log file:
$save_log_file = true;
$log_file_dir = __DIR__ . "/logs";
// Here is some information on how to configure sendmail:
// http://php.net/manual/en/function.mail.php#118210
require('listener.php');
use PaypalIPN;
$ipn = new PaypalIPN();
if ($enable_sandbox) {
    $ipn->useSandbox();
}
$verified = $ipn->verifyIPN();
$data_text = "";
foreach ($_POST as $key => $value) {
    $data_text .= $key . " = " . $value . "\r\n";
}
$test_text = "";
if ($_POST["test_ipn"] == 1) {
    $test_text = "Test ";
}
// Check the receiver email to see if it matches your list of paypal email addresses
$receiver_email_found = false;
foreach ($my_email_addresses as $a) {
    if (strtolower($_POST["receiver_email"]) == strtolower($a)) {
        $receiver_email_found = true;
        break;
    }
}
date_default_timezone_set("America/Los_Angeles");
list($year, $month, $day, $hour, $minute, $second, $timezone) = explode(":", date("Y:m:d:H:i:s:T"));
$date = $year . "-" . $month . "-" . $day;
$timestamp = $date . " " . $hour . ":" . $minute . ":" . $second . " " . $timezone;
$dated_log_file_dir = $log_file_dir . "/" . $year . "/" . $month;
$paypal_ipn_status = "VERIFICATION FAILED";
if ($verified) {
	
    
} elseif ($enable_sandbox) {
    if ($_POST["test_ipn"] != 1) {
        $paypal_ipn_status = "RECEIVED FROM LIVE WHILE SANDBOXED";
    }
} elseif ($_POST["test_ipn"] == 1) {
    $paypal_ipn_status = "RECEIVED FROM SANDBOX WHILE LIVE";
}
if ($save_log_file) {
    // Create log file directory
    if (!is_dir($dated_log_file_dir)) {
        if (!file_exists($dated_log_file_dir)) {
            mkdir($dated_log_file_dir, 0777, true);
            if (!is_dir($dated_log_file_dir)) {
                $save_log_file = false;
            }
        } else {
            $save_log_file = false;
        }
    }
    // Restrict web access to files in the log file directory
    $htaccess_body = "RewriteEngine On" . "\r\n" . "RewriteRule .* - [L,R=404]";
    if ($save_log_file && (!is_file($log_file_dir . "/.htaccess") || file_get_contents($log_file_dir . "/.htaccess") !== $htaccess_body)) {
        if (!is_dir($log_file_dir . "/.htaccess")) {
            file_put_contents($log_file_dir . "/.htaccess", $htaccess_body);
            if (!is_file($log_file_dir . "/.htaccess") || file_get_contents($log_file_dir . "/.htaccess") !== $htaccess_body) {
                $save_log_file = false;
            }
        } else {
            $save_log_file = false;
        }
    }
    if ($save_log_file) {
        // Save data to text file
        file_put_contents($dated_log_file_dir . "/" . $test_text . "paypal_ipn_" . $date . ".txt", "paypal_ipn_status = " . $paypal_ipn_status . "\r\n" . "paypal_ipn_date = " . $timestamp . "\r\n" . $data_text . "\r\n", FILE_APPEND);
    }
}
if ($send_confirmation_email) {
    // Send confirmation email
    mail($confirmation_email_address, $test_text . "PayPal IPN : " . $paypal_ipn_status, "paypal_ipn_status = " . $paypal_ipn_status . "\r\n" . "paypal_ipn_date = " . $timestamp . "\r\n" . $data_text, "From: " . $from_email_address);
}
// Reply with an empty 200 response to indicate to paypal the IPN was received correctly
header("HTTP/1.1 200 OK");