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<?php
/**
* Twenty Nineteen back compat functionality
*
* Prevents Twenty Nineteen 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_Nineteen
* @since Twenty Nineteen 1.0.0
*/
/**
* Prevent switching to Twenty Nineteen on old versions of WordPress.
*
* Switches to the default theme.
*
* @since Twenty Nineteen 1.0.0
*/
function twentynineteen_switch_theme() {
switch_theme( WP_DEFAULT_THEME );
unset( $_GET['activated'] );
add_action( 'admin_notices', 'twentynineteen_upgrade_notice' );
}
add_action( 'after_switch_theme', 'twentynineteen_switch_theme' );
/**
* Adds a message for unsuccessful theme switch.
*
* Prints an update nag after an unsuccessful attempt to switch to
* Twenty Nineteen on WordPress versions prior to 4.7.
*
* @since Twenty Nineteen 1.0.0
*
* @global string $wp_version WordPress version.
*/
function twentynineteen_upgrade_notice() {
$message = sprintf( __( 'Twenty Nineteen requires at least WordPress version 4.7. You are running version %s. Please upgrade and try again.', 'twentynineteen' ), $GLOBALS['wp_version'] );
printf( '<div class="error"><p>%s</p></div>', $message );
}
/**
* Prevents the Customizer from being loaded on WordPress versions prior to 4.7.
*
* @since Twenty Nineteen 1.0.0
*
* @global string $wp_version WordPress version.
*/
function twentynineteen_customize() {
wp_die(
sprintf(
__( 'Twenty Nineteen requires at least WordPress version 4.7. You are running version %s. Please upgrade and try again.', 'twentynineteen' ),
$GLOBALS['wp_version']
),
'',
array(
'back_link' => true,
)
);
}
add_action( 'load-customize.php', 'twentynineteen_customize' );
/**
* Prevents the Theme Preview from being loaded on WordPress versions prior to 4.7.
*
* @since Twenty Nineteen 1.0.0
*
* @global string $wp_version WordPress version.
*/
function twentynineteen_preview() {
if ( isset( $_GET['preview'] ) ) {
wp_die( sprintf( __( 'Twenty Nineteen requires at least WordPress version 4.7. You are running version %s. Please upgrade and try again.', 'twentynineteen' ), $GLOBALS['wp_version'] ) );
}
}
add_action( 'template_redirect', 'twentynineteen_preview' );