Lines:

<?php

/**
 * Twenty Seventeen back compat functionality
 *
 * Prevents Twenty Seventeen from running on WordPress versions prior to 4.7,
 * since this theme is not meant to be backward compatible beyond that and
 * relies on many newer functions and markup changes introduced in 4.7.
 *
 * @package WordPress
 * @subpackage Twenty_Seventeen
 * @since Twenty Seventeen 1.0
 */

/* function twentyseventeen_switch_theme() – Prevent switching to Twenty Seventeen on old versions of WordPress. */
add_action( 'after_switch_theme', 'twentyseventeen_switch_theme' );

/* function twentyseventeen_upgrade_notice() – Adds a message for unsuccessful theme switch. */

/* function twentyseventeen_customize() – Prevents the Customizer from being loaded on WordPress versions prior to 4.7. */
add_action( 'load-customize.php', 'twentyseventeen_customize' );

/* function twentyseventeen_preview() – Prevents the Theme Preview from being loaded on WordPress versions prior to 4.7. */
add_action( 'template_redirect', 'twentyseventeen_preview' );
 

 View on GitHub View on Trac