我不得不编写一个小插件来绕过免费检查来下载和使用。

<?php
/**
 * Plugin Name: Upgrade SSL Bypass
 * Description: The DB-Upgrade process for networks does not work if there\'s an error with your SSL certificate. This plugin bypasses the check by disabling the verification in case of an error.
 * Version:     2013-01-02.1502
 * Author:      Franz Josef Kaiser <[email protected]>
 * Author URI:  http://unserkaiser.com
 * License:     The MIT License (MIT)
 * LicenseURI:  http://www.opensource.org/licenses/mit-license.php
 */
// No direct file access
defined( \'ABSPATH\' ) OR exit;

add_filter( \'http_request_args\', \'upgrade_ssl_bypass\', 10, 2 );
/**
 * Callback for a HTTP request used to switch the
 * SSL verification in case of a WP error response.
 * @param  array  $r   Request arguments
 * @param  string $url Request URL
 * @return array  $r
 */
function upgrade_ssl_bypass( $r, $url )
{
    if (
        ! isset( $_GET )
        OR ! isset( $_GET[\'action\'] )
        OR \'upgrade\' !== $_GET[\'action\']
    )
        return $r;

    if (
        is_wp_error( $response = wp_remote_get(
             admin_url( \'upgrade.php?step=upgrade_db\' )
            ,array(
                 \'timeout\'     => 120
                ,\'httpversion\' => \'1.1\'
             )
        ) )
        AND strstr( $response->get_error_message(), \'SSL: certificate subject name\' )
    )
        add_filter( \'https_ssl_verify\', \'__return_false\' );

    return $r;
}