en basit hali ile

<?php
$server_url = 'http://localhost/guncelleme';

$current_version = '1.0';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $server_url . '/api.php?version=' . $current_version);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);
curl_close($ch);

$latest_version = null;
$update_url = null;
if ($response !== false) {
    $data = json_decode($response, true);
    if (isset($data['version']) && isset($data['update_url'])) {
        $latest_version = $data['version'];
        $update_url = $data['update_url'];
    }
}

if (!is_null($latest_version) && version_compare($latest_version, $current_version, '>')) {
    echo 'Güncelleme mevcut: ' . $latest_version . '<br>';
    echo '<a href="' . $update_url . '">Güncellemeyi indir</a>';
} else {
    echo 'Yazılımınız güncel<br>';
}

?>

api.php

<?php
$latest_version = '1.1';
$update_url = 'http://localhost/guncelleme/update.zip';

$response = array(
    'version' => $latest_version,
    'update_url' => $update_url
);

header('Content-Type: application/json');
echo json_encode($response);

?>