wp-filters.php

<?php

/**
 * Allow Visual Composer update via TGM.
 */
function _allow_vc_update_via_tgm() {
    global $pagenow;

    if ( 'themes.php' === $pagenow && isset( $_GET['page'] ) && 'tgmpa-install-plugins' === $_GET['page'] ) {
        wp_rm_filter( 'upgrader_pre_download', array( 'Vc_Updater', 'preUpgradeFilter' ) );
    }
}
add_action( 'admin_init', '_allow_vc_update_via_tgm' );

if ( ! function_exists( 'wp_rm_filter' ) ) :
    /**
     * Removes a function from a specified filter hook.
     *
     * @param  string   $tag      The filter hook to which the function to be removed is hooked.
     * @param  callable $remove   The name of the function which should be removed.
     * @param  int      $priority Optional. The priority of the function. Default 10.
     * @return bool
     */
    function wp_rm_filter( $tag, $remove, $priority = 10 ) {
        global $wp_filter;

        if ( ! is_array( $remove ) ) {
            return remove_filter( $tag, $remove, $priority );
        }

        // Extract class and method name.
        list( $class, $method ) = $remove;

        if ( isset( $wp_filter[ $tag ][ $priority ] ) ) {
            $k =& $wp_filter[ $tag ][ $priority ];

            foreach ( $k as $id => $filter ) {
                if ( isset( $filter['function'] ) && is_array( $filter['function'] ) ) {
                    if ( is_a( $filter['function'][0], $class ) && $method === $filter['function'][1] ) {
                        unset( $k[ $id ] );
                        return true;
                    }
                }
            }
        }

        return false;
    }
endif;