1 <?php

     2 /**

     3  * Twenty Seventeen back compat functionality

     4  *

     5  * Prevents Twenty Seventeen from running on WordPress versions prior to 4.7,

     6  * since this theme is not meant to be backward compatible beyond that and

     7  * relies on many newer functions and markup changes introduced in 4.7.

     8  *

     9  * @package WordPress

    10  * @subpackage Twenty_Seventeen

    11  * @since Twenty Seventeen 1.0

    12  */

    13 

    14 /**

    15  * Prevent switching to Twenty Seventeen on old versions of WordPress.

    16  *

    17  * Switches to the default theme.

    18  *

    19  * @since Twenty Seventeen 1.0

    20  */

    21 function twentyseventeen_switch_theme() {

    22 	switch_theme( WP_DEFAULT_THEME );

    23 	unset( $_GET['activated'] );

    24 	add_action( 'admin_notices', 'twentyseventeen_upgrade_notice' );

    25 }

    26 add_action( 'after_switch_theme', 'twentyseventeen_switch_theme' );

    27 

    28 /**

    29  * Adds a message for unsuccessful theme switch.

    30  *

    31  * Prints an update nag after an unsuccessful attempt to switch to

    32  * Twenty Seventeen on WordPress versions prior to 4.7.

    33  *

    34  * @since Twenty Seventeen 1.0

    35  *

    36  * @global string $wp_version WordPress version.

    37  */

    38 function twentyseventeen_upgrade_notice() {

    39 	$message = sprintf( __( 'Twenty Seventeen requires at least WordPress version 4.7. You are running version %s. Please upgrade and try again.', 'twentyseventeen' ), $GLOBALS['wp_version'] );

    40 	printf( '<div class="error"><p>%s</p></div>', $message );

    41 }

    42 

    43 /**

    44  * Prevents the Customizer from being loaded on WordPress versions prior to 4.7.

    45  *

    46  * @since Twenty Seventeen 1.0

    47  *

    48  * @global string $wp_version WordPress version.

    49  */

    50 function twentyseventeen_customize() {

    51 	wp_die( sprintf( __( 'Twenty Seventeen requires at least WordPress version 4.7. You are running version %s. Please upgrade and try again.', 'twentyseventeen' ), $GLOBALS['wp_version'] ), '', array(

    52 		'back_link' => true,

    53 	) );

    54 }

    55 add_action( 'load-customize.php', 'twentyseventeen_customize' );

    56 

    57 /**

    58  * Prevents the Theme Preview from being loaded on WordPress versions prior to 4.7.

    59  *

    60  * @since Twenty Seventeen 1.0

    61  *

    62  * @global string $wp_version WordPress version.

    63  */

    64 function twentyseventeen_preview() {

    65 	if ( isset( $_GET['preview'] ) ) {

    66 		wp_die( sprintf( __( 'Twenty Seventeen requires at least WordPress version 4.7. You are running version %s. Please upgrade and try again.', 'twentyseventeen' ), $GLOBALS['wp_version'] ) );

    67 	}

    68 }

    69 add_action( 'template_redirect', 'twentyseventeen_preview' );