if ( ! is_array( $cron ) ) {
		return array();
	}

	if ( ! isset( $cron['version'] ) ) {
		$cron = _upgrade_cron_array( $cron );
	}

	unset( $cron['version'] );

	return $cron;
}

/**
 * Updates the cron option with the new cron array.
 *
 * @since 2.1.0
 * @since 5.1.0 Return value modified to outcome of update_option().
 * @since 5.7.0 The `$wp_error` parameter was added.
 *
 * @access private
 *
 * @param array[] $cron     Array of cron info arrays from _get_cron_array().
 * @param bool    $wp_error Optional. Whether to return a WP_Error on failure. Default false.
 * @return bool|WP_Error True if cron array updated. False or WP_Error on failure.
 */
function _set_cron_array( $cron, $wp_error = false ) {
	if ( ! is_array( $cron ) ) {
		$cron = array();
	}

	$cron['version'] = 2;

	$result = update_option( 'cron', $cron, true );

	if ( $wp_error && ! $result ) {
		return new WP_Error(
			'could_not_set',
			__( 'The cron event list could not be saved.' )
		);
	}

	return $result;
}

/**
 * Upgrades a cron info array.
 *
 * This function upgrades the cron info array to version 2.
 *
 * @since 2.1.0
 * @access private
 *
 * @param array $cron Cron info array from _get_cron_array().
 * @return array An upgraded cron info array.
 */
function _upgrade_cron_array( $cron ) {
	if ( isset( $cron['version'] ) && 2 === $cron['version'] ) {
		return $cron;
	}

	$new_cron = array();

	foreach ( (array) $cron as $timestamp => $hooks ) {
		foreach ( (array) $hooks as $hook => $args ) {
			$key = md5( serialize( $args['args'] ) );

			$new_cron[ $timestamp ][ $hook ][ $key ] = $args;
		}
	}

	$new_cron['version'] = 2;

	update_option( 'cron', $new_cron, true );

	return $new_cron;
}