Trigger which version Whatsapp to sent messages

index.php

<?php
/**
Thanks stackoverflow
*/
function getOS($user_agent) {
$os_array =   array(
        '/windows nt 10/i'     =>  'Windows 10',
        '/windows nt 6.3/i'     =>  'Windows 8.1',
        '/windows nt 6.2/i'     =>  'Windows 8',
        '/windows nt 6.1/i'     =>  'Windows 7',
        '/windows nt 6.0/i'     =>  'Windows Vista',
        '/windows nt 5.2/i'     =>  'Windows Server 2003/XP x64',
        '/windows nt 5.1/i'     =>  'Windows XP',
        '/windows xp/i'         =>  'Windows XP',
        '/windows nt 5.0/i'     =>  'Windows 2000',
        '/windows me/i'         =>  'Windows ME',
        '/win98/i'              =>  'Windows 98',
        '/win95/i'              =>  'Windows 95',
        '/win16/i'              =>  'Windows 3.11',
        '/macintosh|mac os x/i' =>  'Mac OS X',
        '/mac_powerpc/i'        =>  'Mac OS 9',
        '/linux/i'              =>  'Linux',
        '/ubuntu/i'             =>  'Ubuntu',
        '/iphone/i'             =>  'iPhone',
        '/ipod/i'               =>  'iPod',
        '/ipad/i'               =>  'iPad',
        '/android/i'            =>  'Android',
        '/blackberry/i'         =>  'BlackBerry',
        '/webos/i'              =>  'Mobile'
    );

    foreach ($os_array as $regex => $value) { 

        if (preg_match($regex, $user_agent)) {
            $os_platform    =   $value;
        }

    }   

    return $os_platform;

}
/**
end stackoverflow
*/
$user_agent = $_SERVER['HTTP_USER_AGENT'];

$os = getOS($user_agent);
$text = urlencode($_GET['text']);
$phone = $_GET['phone'];

if(in_array($os,array('Android','iPhone','Blackberry','Mobile'))) {
    header("Location:whatsapp://send?text=".$text."&phone=+".$phone);
}
else {
    header("Location:https://web.whatsapp.com/send?text=".$text."&phone=+".$phone);
}


?>