.
	 * @param string $old_email The old site admin email address.
	 * @param string $new_email The new site admin email address.
	 */
	$send = apply_filters( 'send_site_admin_email_change_email', $send, $old_email, $new_email );

	if ( ! $send ) {
		return;
	}

	/* translators: Do not translate OLD_EMAIL, NEW_EMAIL, SITENAME, SITEURL: those are placeholders. */
	$email_change_text = __(
		'Hi,

This notice confirms that the admin email address was changed on ###SITENAME###.

The new admin email address is ###NEW_EMAIL###.

This email has been sent to ###OLD_EMAIL###

Regards,
All at ###SITENAME###
###SITEURL###'
	);

	$email_change_email = array(
		'to'      => $old_email,
		/* translators: Site admin email change notification email subject. %s: Site title. */
		'subject' => __( '[%s] Admin Email Changed' ),
		'message' => $email_change_text,
		'headers' => '',
	);

	// Get site name.
	$site_name = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );

	/**
	 * Filters the contents of the email notification sent when the site admin email address is changed.
	 *
	 * @since 4.9.0
	 *
	 * @param array $email_change_email {
	 *     Used to build wp_mail().
	 *
	 *     @type string $to      The intended recipient.
	 *     @type string $subject The subject of the email.
	 *     @type string $message The content of the email.
	 *         The following strings have a special meaning and will get replaced dynamically:
	 *         - ###OLD_EMAIL### The old site admin email address.
	 *         - ###NEW_EMAIL### The new site admin email address.
	 *         - ###SITENAME###  The name of the site.
	 *         - ###SITEURL###   The URL to the site.
	 *     @type string $headers Headers.
	 * }
	 * @param string $old_email The old site admin email address.
	 * @param string $new_email The new site admin email address.
	 */
	$email_change_email = apply_filters( 'site_admin_email_change_email', $email_change_email, $old_email, $new_email );

	$email_change_email['message'] = str_replace( '###OLD_EMAIL###', $old_email, $email_change_email['message'] );
	$email_change_email['message'] = str_replace( '###NEW_EMAIL###', $new_email, $email_change_email['message'] );
	$email_change_email['message'] = str_replace( '###SITENAME###', $site_name, $email_change_email['message'] );
	$email_change_email['message'] = str_replace( '###SITEURL###', home_url(), $email_change_email['message'] );

	wp_mail(
		$email_change_email['to'],
		sprintf(
			$email_change_email['subject'],
			$site_name
		),
		$email_change_email['message'],
		$email_change_email['headers']
	);
}

/**
 * Return an anonymized IPv4 or IPv6 address.
 *
 * @since 4.9.6 Abstracted from `WP_Community_Events::get_unsafe_client_ip()`.
 *
 * @param string $ip_addr       The IPv4 or IPv6 address to be anonymized.
 * @param bool   $ipv6_fallback Optional. Whether to return the original IPv6 address if the needed functions
 *                              to anonymize it are not present. Default false, return `::` (unspecified address).
 * @return string  The anonymized IP address.
 */
function wp_privacy_anonymize_ip( $ip_addr, $ipv6_fallback = false ) {
	// Detect what kind of IP address this is.
	$ip_prefix = '';
	$is_ipv6   = substr_count( $ip_addr, ':' ) > 1;
	$is_ipv4   = ( 3 === substr_count( $ip_addr, '.' ) );

	if ( $is_ipv6 && $is_ipv4 ) {
		// IPv6 compatibility mode, temporarily strip the IPv6 part, and treat it like IPv4.
		$ip_prefix = '::ffff:';
		$ip_addr   = preg_replace( '/^\[?[0-9a-f:]*:/i', '', $ip_addr );
		$ip_addr   = str_replace( ']', '', $ip_addr );
		$is_ipv6   = false;
	}

	if ( $is_ipv6 ) {
		// IPv6 addresses will always be enclosed in [] if there's a port.
		$left_bracket  = strpos( $ip_addr, '[' );
		$right_bracket = strpos( $ip_addr, ']' );
		$percent       = strpos( $ip_addr, '%' );
		$netmask       = 'ffff:ffff:ffff:ffff:0000:0000:0000:0000';

		// Strip the port (and [] from IPv6 addresses), if they exist.
		if ( false !== $left_bracket && false !== $right_bracket ) {
			$ip_addr = substr( $ip_addr, $left_bracket + 1, $right_bracket - $left_bracket - 1 );
		} elseif ( false !== $left_bracket || false !== $right_bracket ) {
			// The IP has one bracket, but not both, so it's malformed.
			return '::';
		}

		// Strip the reachability scope.
		if ( false !== $percent ) {
			$ip_addr = substr( $ip_addr, 0, $percent );
		}

		// No invalid characters should be left.
		if ( preg_match( '/[^0-9a-f:]/i', $ip_addr ) ) {
			return '::';
		}

		// Partially anonymize the IP by reducing it to the corresponding network ID.
		if ( function_exists( 'inet_pton' ) && function_exists( 'inet_ntop' ) ) {
			$ip_addr = inet_ntop( inet_pton( $ip_addr ) & inet_pton( $netmask ) );
			if ( false === $ip_addr ) {
				return '::';
			}
		} elseif ( ! $ipv6_fallback ) {
			return '::';
		}
	} elseif ( $is_ipv4 ) {
		// Strip any port and partially anonymize the IP.
		$last_octet_position = strrpos( $ip_addr, '.' );
		$ip_addr             = substr( $ip_addr, 0, $last_octet_position ) . '.0';
	} else {
		return '0.0.0.0';
	}

	// Restore the IPv6 prefix to compatibility mode addresses.
	return $ip_prefix . $ip_addr;
}

/**
 * Return uniform "anonymous" data by type.
 *
 * @since 4.9.6
 *
 * @param string $type The type of data to be anonymized.
 * @param string $data Optional The data to be anonymized.
 * @return string The anonymous data for the requested type.
 */
function wp_privacy_anonymize_data( $type, $data = '' ) {

	switch ( $type ) {
		case 'email':
			$anonymous = 'deleted@site.invalid';
			break;
		case 'url':
			$anonymous = 'https://site.invalid';
			break;
		case 'ip':
			$anonymous = wp_privacy_anonymize_ip( $data );
			break;
		case 'date':
			$anonymous = '0000-00-00 00:00:00';
			break;
		case 'text':
			/* translators: Deleted text. */
			$anonymous = __( '[deleted]' );
			break;
		case 'longtext':
			/* translators: Deleted long text. */
			$anonymous = __( 'This content was deleted by the author.' );
			break;
		default:
			$anonymous = '';
			break;
	}

	/**
	 * Filters the anonymous data for each type.
	 *
	 * @since 4.9.6
	 *
	 * @param string $anonymous Anonymized data.
	 * @param string $type      Type of the data.
	 * @param string $data      Original data.
	 */
	return apply_filters( 'wp_privacy_anonymize_data', $anonymous, $type, $data );
}

/**
 * Returns the directory used to store personal data export files.
 *
 * @since 4.9.6
 *
 * @see wp_privacy_exports_url
 *
 * @return string Exports directory.
 */
function wp_privacy_exports_dir() {
	$upload_dir  = wp_upload_dir();
	$exports_dir = trailingslashit( $upload_dir['basedir'] ) . 'wp-personal-data-exports/';

	/**
	 * Filters the directory used to store personal data export files.
	 *
	 * @since 4.9.6
	 * @since 5.5.0 Exports now use relative paths, so changes to the directory
	 *              via this filter should be reflected on the server.
	 *
	 * @param string $exports_dir Exports directory.
	 */
	return apply_filters( 'wp_privacy_exports_dir', $exports_dir );
}

/**
 * Returns the URL of the directory used to store personal data export files.
 *
 * @since 4.9.6
 *
 * @see wp_privacy_exports_dir
 *
 * @return string Exports directory URL.
 */
function wp_privacy_exports_url() {
	$upload_dir  = wp_upload_dir();
	$exports_url = trailingslashit( $upload_dir['baseurl'] ) . 'wp-personal-data-exports/';

	/**
	 * Filters the URL of the directory used to store personal data export files.
	 *
	 * @since 4.9.6
	 * @since 5.5.0 Exports now use relative paths, so changes to the directory URL
	 *              via this filter should be reflected on the server.
	 *
	 * @param string $exports_url Exports directory URL.
	 */
	return apply_filters( 'wp_privacy_exports_url', $exports_url );
}

/**
 * Schedule a `WP_Cron` job to delete expired export files.
 *
 * @since 4.9.6
 */
function wp_schedule_delete_old_privacy_export_files() {
	if ( wp_installing() ) {
		return;
	}

	if ( ! wp_next_scheduled( 'wp_privacy_delete_old_export_files' ) ) {
		wp_schedule_event( time(), 'hourly', 'wp_privacy_delete_old_export_files' );
	}
}

/**
 * Cleans up export files older than three days old.
 *
 * The export files are stored in `wp-content/uploads`, and are therefore publicly
 * accessible. A CSPRN is appended to the filename to mitigate the risk of an
 * unauthorized person downloading the file, but it is still possible. Deleting
 * the file after the data subject has had a chance to delete it adds an additional
 * layer of protection.
 *
 * @since 4.9.6
 */
function wp_privacy_delete_old_export_files() {
	$exports_dir = wp_privacy_exports_dir();
	if ( ! is_dir( $exports_dir ) ) {
		return;
	}

	require_once ABSPATH . 'wp-admin/includes/file.php';
	$export_files = list_files( $exports_dir, 100, array( 'index.php' ) );

	/**
	 * Filters the lifetime, in seconds, of a personal data export file.
	 *
	 * By default, the lifetime is 3 days. Once the file reaches that age, it will automatically
	 * be deleted by a cron job.
	 *
	 * @since 4.9.6
	 *
	 * @param int $expiration The expiration age of the export, in seconds.
	 */
	$expiration = apply_filters( 'wp_privacy_export_expiration', 3 * DAY_IN_SECONDS );

	foreach ( (array) $export_files as $export_file ) {
		$file_age_in_seconds = time() - filemtime( $export_file );

		if ( $expiration < $file_age_in_seconds ) {
			unlink( $export_file );
		}
	}
}

/**
 * Gets the URL to learn more about updating the PHP version the site is running on.
 *
 * This URL can be overridden by specifying an environment variable `WP_UPDATE_PHP_URL` or by using the
 * {@see 'wp_update_php_url'} filter. Providing an empty string is not allowed and will result in the
 * default URL being used. Furthermore the page the URL links to should preferably be localized in the
 * site language.
 *
 * @since 5.1.0
 *
 * @return string URL to learn more about updating PHP.
 */
function wp_get_update_php_url() {
	$default_url = wp_get_default_update_php_url();

	$update_url = $default_url;
	if ( false !== getenv( 'WP_UPDATE_PHP_URL' ) ) {
		$update_url = getenv( 'WP_UPDATE_PHP_URL' );
	}

	/**
	 * Filters the URL to learn more about updating the PHP version the site is running on.
	 *
	 * Providing an empty string is not allowed and will result in the default URL being used. Furthermore
	 * the page the URL links to should preferably be localized in the site language.
	 *
	 * @since 5.1.0
	 *
	 * @param string $update_url URL to learn more about updating PHP.
	 */
	$update_url = apply_filters( 'wp_update_php_url', $update_url );

	if ( empty( $update_url ) ) {
		$update_url = $default_url;
	}

	return $update_url;
}

/**
 * Gets the default URL to learn more about updating the PHP version the site is running on.
 *
 * Do not use this function to retrieve this URL. Instead, use {@see wp_get_update_php_url()} when relying on the URL.
 * This function does not allow modifying the returned URL, and is only used to compare the actually used URL with the
 * default one.
 *
 * @since 5.1.0
 * @access private
 *
 * @return string Default URL to learn more about updating PHP.
 */
function wp_get_default_update_php_url() {
	return _x( 'https://wordpress.org/support/update-php/', 'localized PHP upgrade information page' );
}

/**
 * Prints the default annotation for the web host altering the "Update PHP" page URL.
 *
 * This function is to be used after {@see wp_get_update_php_url()} to display a consistent
 * annotation if the web host has altered the default "Update PHP" page URL.
 *
 * @since 5.1.0
 * @since 5.2.0 Added the `$before` and `$after` parameters.
 *
 * @param string $before Markup to output before the annotation. Default `<p class="description">`.
 * @param string $after  Markup to output after the annotation. Default `</p>`.
 */
function wp_update_php_annotation( $before = '<p class="description">', $after = '</p>' ) {
	$annotation = wp_get_update_php_annotation();

	if ( $annotation ) {
		echo $before . $annotation . $after;
	}
}

/**
 * Returns the default annotation for the web hosting altering the "Update PHP" page URL.
 *
 * This function is to be used after {@see wp_get_update_php_url()} to return a consistent
 * annotation if the web host has altered the default "Update PHP" page URL.
 *
 * @since 5.2.0
 *
 * @return string Update PHP page annotation. An empty string if no custom URLs are provided.
 */
function wp_get_update_php_annotation() {
	$update_url  = wp_get_update_php_url();
	$default_url = wp_get_default_update_php_url();

	if ( $update_url === $default_url ) {
		return '';
	}

	$annotation = sprintf(
		/* translators: %s: Default Update PHP page URL. */
		__( 'This resource is provided by your web host, and is specific to your site. For more information, <a href="%s" target="_blank">see the official WordPress documentation</a>.' ),
		esc_url( $default_url )
	);

	return $annotation;
}

/**
 * Gets the URL for directly updating the PHP version the site is running on.
 *
 * A URL will only be returned if the `WP_DIRECT_UPDATE_PHP_URL` environment variable is specified or
 * by using the {@see 'wp_direct_php_update_url'} filter. This allows hosts to send users directly to
 * the page where they can update PHP to a newer version.
 *
 * @since 5.1.1
 *
 * @return string URL for directly updating PHP or empty string.
 */
function wp_get_direct_php_update_url() {
	$direct_update_url = '';

	if ( false !== getenv( 'WP_DIRECT_UPDATE_PHP_URL' ) ) {
		$direct_update_url = getenv( 'WP_DIRECT_UPDATE_PHP_URL' );
	}

	/**
	 * Filters the URL for directly updating the PHP version the site is running on from the host.
	 *
	 * @since 5.1.1
	 *
	 * @param string $direct_update_url URL for directly updating PHP.
	 */
	$direct_update_url = apply_filters( 'wp_direct_php_update_url', $direct_update_url );

	return $direct_update_url;
}

/**
 * Display a button directly linking to a PHP update process.
 *
 * This provides hosts with a way for users to be sent directly to their PHP update process.
 *
 * The button is only displayed if a URL is returned by `wp_get_direct_php_update_url()`.
 *
 * @since 5.1.1
 */
function wp_direct_php_update_button() {
	$direct_update_url = wp_get_direct_php_update_url();

	if ( empty( $direct_update_url ) ) {
		return;
	}

	echo '<p class="button-container">';
	printf(
		'<a class="button button-primary" href="%1$s" target="_blank" rel="noopener">%2$s <span class="screen-reader-text">%3$s</span><span aria-hidden="true" class="dashicons dashicons-external"></span></a>',
		esc_url( $direct_update_url ),
		__( 'Update PHP' ),
		/* translators: Accessibility text. */
		__( '(opens in a new tab)' )
	);
	echo '</p>';
}

/**
 * Gets the URL to learn more about updating the site to use HTTPS.
 *
 * This URL can be overridden by specifying an environment variable `WP_UPDATE_HTTPS_URL` or by using the
 * {@see 'wp_update_https_url'} filter. Providing an empty string is not allowed and will result in the
 * default URL being used. Furthermore the page the URL links to should preferably be localized in the
 * site language.
 *
 * @since 5.7.0
 *
 * @return string URL to learn more about updating to HTTPS.
 */
function wp_get_update_https_url() {
	$default_url = wp_get_default_update_https_url();

	$update_url = $default_url;
	if ( false !== getenv( 'WP_UPDATE_HTTPS_URL' ) ) {
		$update_url = getenv( 'WP_UPDATE_HTTPS_URL' );
	}

	/**
	 * Filters the URL to learn more about updating the HTTPS version the site is running on.
	 *
	 * Providing an empty string is not allowed and will result in the default URL being used. Furthermore
	 * the page the URL links to should preferably be localized in the site language.
	 *
	 * @since 5.7.0
	 *
	 * @param string $update_url URL to learn more about updating HTTPS.
	 */
	$update_url = apply_filters( 'wp_update_https_url', $update_url );
	if ( empty( $update_url ) ) {
		$update_url = $default_url;
	}

	return $update_url;
}

/**
 * Gets the default URL to learn more about updating the site to use HTTPS.
 *
 * Do not use this function to retrieve this URL. Instead, use {@see wp_get_update_https_url()} when relying on the URL.
 * This function does not allow modifying the returned URL, and is only used to compare the actually used URL with the
 * default one.
 *
 * @since 5.7.0
 * @access private
 *
 * @return string Default URL to learn more about updating to HTTPS.
 */
function wp_get_default_update_https_url() {
	/* translators: Documentation explaining HTTPS and why it should be used. */
	return __( 'https://wordpress.org/support/article/why-should-i-use-https/' );
}

/**
 * Gets the URL for directly updating the site to use HTTPS.
 *
 * A URL will only be returned if the `WP_DIRECT_UPDATE_HTTPS_URL` environment variable is specified or
 * by using the {@see 'wp_direct_update_https_url'} filter. This allows hosts to send users directly to
 * the page where they can update their site to use HTTPS.
 *
 * @since 5.7.0
 *
 * @return string URL for directly updating to HTTPS or empty string.
 */
function wp_get_direct_update_https_url() {
	$direct_update_url = '';

	if ( false !== getenv( 'WP_DIRECT_UPDATE_HTTPS_URL' ) ) {
		$direct_update_url = getenv( 'WP_DIRECT_UPDATE_HTTPS_URL' );
	}

	/**
	 * Filters the URL for directly updating the PHP version the site is running on from the host.
	 *
	 * @since 5.7.0
	 *
	 * @param string $direct_update_url URL for directly updating PHP.
	 */
	$direct_update_url = apply_filters( 'wp_direct_update_https_url', $direct_update_url );

	return $direct_update_url;
}

/**
 * Get the size of a directory.
 *
 * A helper function that is used primarily to check whether
 * a blog has exceeded its allowed upload space.
 *
 * @since MU (3.0.0)
 * @since 5.2.0 $max_execution_time parameter added.
 *
 * @param string $directory Full path of a directory.
 * @param int    $max_execution_time Maximum time to run before giving up. In seconds.
 *                                   The timeout is global and is measured from the moment WordPress started to load.
 * @return int|false|null Size in bytes if a valid directory. False if not. Null if timeout.
 */
function get_dirsize( $directory, $max_execution_time = null ) {

	// Exclude individual site directories from the total when checking the main site of a network,
	// as they are subdirectories and should not be counted.
	if ( is_multisite() && is_main_site() ) {
		$size = recurse_dirsize( $directory, $directory . '/sites', $max_execution_time );
	} else {
		$size = recurse_dirsize( $directory, null, $max_execution_time );
	}

	return $size;
}

/**
 * Get the size of a directory recursively.
 *
 * Used by get_dirsize() to get a directory size when it contains other directories.
 *
 * @since MU (3.0.0)
 * @since 4.3.0 The `$exclude` parameter was added.
 * @since 5.2.0 The `$max_execution_time` parameter was added.
 * @since 5.6.0 The `$directory_cache` parameter was added.
 *
 * @param string       $directory          Full path of a directory.
 * @param string|array $exclude            Optional. Full path of a subdirectory to exclude from the total,
 *                                         or array of paths. Expected without trailing slash(es).
 * @param int          $max_execution_time Maximum time to run before giving up. In seconds. The timeout is global
 *                                         and is measured from the moment WordPress started to load.
 * @param array        $directory_cache    Optional. Array of cached directory paths.
 *
 * @return int|false|null Size in bytes if a valid directory. False if not. Null if timeout.
 */
function recurse_dirsize( $directory, $exclude = null, $max_execution_time = null, &$directory_cache = null ) {
	$directory  = untrailingslashit( $directory );
	$save_cache = false;

	if ( ! isset( $directory_cache ) ) {
		$directory_cache = get_transient( 'dirsize_cache' );
		$save_cache      = true;
	}

	if ( isset( $directory_cache[ $directory ] ) && is_int( $directory_cache[ $directory ] ) ) {
		return $directory_cache[ $directory ];
	}

	if ( ! file_exists( $directory ) || ! is_dir( $directory ) || ! is_readable( $directory ) ) {
		return false;
	}

	if (
		( is_string( $exclude ) && $directory === $exclude ) ||
		( is_array( $exclude ) && in_array( $directory, $exclude, true ) )
	) {
		return false;
	}

	if ( null === $max_execution_time ) {
		// Keep the previous behavior but attempt to prevent fatal errors from timeout if possible.
		if ( function_exists( 'ini_get' ) ) {
			$max_execution_time = ini_get( 'max_execution_time' );
		} else {
			// Disable...
			$max_execution_time = 0;
		}

		// Leave 1 second "buffer" for other operations if $max_execution_time has reasonable value.
		if ( $max_execution_time > 10 ) {
			$max_execution_time -= 1;
		}
	}

	/**
	 * Filters the amount of storage space used by one directory and all its children, in megabytes.
	 *
	 * Return the actual used space to short-circuit the recursive PHP file size calculation
	 * and use something else, like a CDN API or native operating system tools for better performance.
	 *
	 * @since 5.6.0
	 *
	 * @param int|false $space_used The amount of used space, in bytes. Default false.
	 */
	$size = apply_filters( 'pre_recurse_dirsize', false, $directory, $exclude, $max_execution_time, $directory_cache );

	if ( false === $size ) {
		$size = 0;

		$handle = opendir( $directory );
		if ( $handle ) {
			while ( ( $file = readdir( $handle ) ) !== false ) {
				$path = $directory . '/' . $file;
				if ( '.' !== $file && '..' !== $file ) {
					if ( is_file( $path ) ) {
						$size += filesize( $path );
					} elseif ( is_dir( $path ) ) {
						$handlesize = recurse_dirsize( $path, $exclude, $max_execution_time, $directory_cache );
						if ( $handlesize > 0 ) {
							$size += $handlesize;
						}
					}

					if ( $max_execution_time > 0 && microtime( true ) - WP_START_TIMESTAMP > $max_execution_time ) {
						// Time exceeded. Give up instead of risking a fatal timeout.
						$size = null;
						break;
					}
				}
			}
			closedir( $handle );
		}
	}

	$directory_cache[ $directory ] = $size;

	// Only write the transient on the top level call and not on recursive calls.
	if ( $save_cache ) {
		set_transient( 'dirsize_cache', $directory_cache );
	}

	return $size;
}

/**
 * Cleans directory size cache used by recurse_dirsize().
 *
 * Removes the current directory and all parent directories from the `dirsize_cache` transient.
 *
 * @since 5.6.0
 *
 * @param string $path Full path of a directory or file.
 */
function clean_dirsize_cache( $path ) {
	$directory_cache = get_transient( 'dirsize_cache' );

	if ( empty( $directory_cache ) ) {
		return;
	}

	$path = untrailingslashit( $path );
	unset( $directory_cache[ $path ] );

	while ( DIRECTORY_SEPARATOR !== $path && '.' !== $path && '..' !== $path ) {
		$path = dirname( $path );
		unset( $directory_cache[ $path ] );
	}

	set_transient( 'dirsize_cache', $directory_cache );
}

/**
 * Checks compatibility with the current WordPress version.
 *
 * @since 5.2.0
 *
 * @param string $required Minimum required WordPress version.
 * @return bool True if required version is compatible or empty, false if not.
 */
function is_wp_version_compatible( $required ) {
	return empty( $required ) || version_compare( get_bloginfo( 'version' ), $required, '>=' );
}

/**
 * Checks compatibility with the current PHP version.
 *
 * @since 5.2.0
 *
 * @param string $required Minimum required PHP version.
 * @return bool True if required version is compatible or empty, false if not.
 */
function is_php_version_compatible( $required ) {
	return empty( $required ) || version_compare( phpversion(), $required, '>=' );
}

/**
 * Check if two numbers are nearly the same.
 *
 * This is similar to using `round()` but the precision is more fine-grained.
 *
 * @since 5.3.0
 *
 * @param int|float $expected  The expected value.
 * @param int|float $actual    The actual number.
 * @param int|float $precision The allowed variation.
 * @return bool Whether the numbers match whithin the specified precision.
 */
function wp_fuzzy_number_match( $expected, $actual, $precision = 1 ) {
	return abs( (float) $expected - (float) $actual ) <= $precision;
}