index.php

<?php
$valid = true;
if (phpversion() < "5.6") {
    echo "ERROR: PHP 5.6 or higher is required.<br />";
    exit(0);
}

if (!extension_loaded('mysqli')) {
    echo "ERROR: The requested PHP mysqli extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('pdo')) {
    echo "ERROR: The requested PHP pdo extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('curl')) {
    echo "ERROR: The requested PHP curl extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('openssl')) {
    echo "ERROR: The requested PHP openssl extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('iconv') && !function_exists('iconv')) {
    echo "ERROR: The requested PHP iconv extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('mbstring')) {
    echo "ERROR: The requested PHP Mbstring extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('gd')) {
    echo "ERROR: The requested PHP gd extension is missing from your system.<br />";
    exit(0);
}

if (!extension_loaded('zip')) {
    echo "ERROR: The requested PHP zip extension is missing from your system.<br />";
    exit(0);
}

$url_f_open = ini_get('allow_url_fopen');
if ($url_f_open != "1" && $url_f_open != 'On') {
    echo "ERROR: Please enable the <strong>allow_url_fopen</strong> setting to continue.<br />";
    exit(0);
}

if (!empty(ini_get('open_basedir'))) {
    echo "ERROR: Please disable the <strong>open_basedir</strong> setting to continue.<br />";
    exit(0);
}

if (!function_exists('proc_open')) {
    echo "ERROR: Please enable <strong>proc_open</strong> php function setting to continue.<br />";
    exit(0);
}

if (!function_exists('curl_version')) {
    echo "ERROR: Please enable <strong>Curl</strong> php function setting to continue.<br />";
    exit(0);
}

if (!function_exists('base64_decode')) {
    echo "ERROR: Please enable <strong>base64_decode</strong> php function setting to continue.<br />";
    exit(0);
}

if (!(file_exists('application/storage/app') && is_dir('application/storage/app') && (is_writable('application/storage/app')))) {
    echo "ERROR: The directory [application/storage/app] must be writable by the web server.<br />";
    $valid = false;
}
if (!(file_exists('application/storage/framework') && is_dir('application/storage/framework') && (is_writable('application/storage/framework')))) {
    echo "ERROR: The directory [application/storage/framework] must be writable by the web server.<br />";
    $valid = false;
}
if (!(file_exists('application/storage/logs') && is_dir('application/storage/logs') && (is_writable('application/storage/logs')))) {
    echo "ERROR: The directory [application/storage/logs] must be writable by the web server.<br />";
    $valid = false;
}
if (!(file_exists('application/bootstrap/cache') && is_dir('application/bootstrap/cache') && (is_writable('application/bootstrap/cache')))) {
    echo "ERROR: The directory [application/bootstrap/cache] must be writable by the web server.<br />";
    $valid = false;
}

if($valid) {
    require 'main.php';
}