diff --git a/wp-content/themes/twentyseventeen/functions.php b/wp-content/themes/twentyseventeen/functions.php
index ebd65c0f9a..0ce0dccb09 100644
--- a/wp-content/themes/twentyseventeen/functions.php
+++ b/wp-content/themes/twentyseventeen/functions.php
@@ -585,6 +585,30 @@ function twentyseventeen_widget_tag_cloud_args( $args ) {
 }
 add_filter( 'widget_tag_cloud_args', 'twentyseventeen_widget_tag_cloud_args' );
 
+/**
+ * Get unique ID.
+ *
+ * This is a PHP implementation of Underscore's uniqueId method. A static variable
+ * contains an integer that is incremented with each call. This number is returned
+ * with the optional prefix. As such the returned value is not universally unique,
+ * but it is unique across the life of the PHP process.
+ *
+ * @since Twenty Seventeen 2.0
+ * @see wp_unique_id() Themes requiring WordPress 5.0.3 and greater should use this instead.
+ *
+ * @staticvar int $id_counter
+ *
+ * @param string $prefix Prefix for the returned ID.
+ * @return string Unique ID.
+ */
+function twentyseventeen_unique_id( $prefix = '' ) {
+	static $id_counter = 0;
+	if ( function_exists( 'wp_unique_id' ) ) {
+		return wp_unique_id( $prefix );
+	}
+	return $prefix . (string) ++$id_counter;
+}
+
 /**
  * Implement the Custom Header feature.
  */
diff --git a/wp-content/themes/twentyseventeen/inc/icon-functions.php b/wp-content/themes/twentyseventeen/inc/icon-functions.php
index 3425f740df..0a3c513331 100644
--- a/wp-content/themes/twentyseventeen/inc/icon-functions.php
+++ b/wp-content/themes/twentyseventeen/inc/icon-functions.php
@@ -74,7 +74,7 @@ function twentyseventeen_get_svg( $args = array() ) {
 	 */
 	if ( $args['title'] ) {
 		$aria_hidden     = '';
-		$unique_id       = uniqid();
+		$unique_id       = twentyseventeen_unique_id();
 		$aria_labelledby = ' aria-labelledby="title-' . $unique_id . '"';
 
 		if ( $args['desc'] ) {
diff --git a/wp-content/themes/twentyseventeen/searchform.php b/wp-content/themes/twentyseventeen/searchform.php
index 519c879375..4a38cddafa 100644
--- a/wp-content/themes/twentyseventeen/searchform.php
+++ b/wp-content/themes/twentyseventeen/searchform.php
@@ -10,7 +10,7 @@
 
 ?>
 
-<?php $unique_id = esc_attr( uniqid( 'search-form-' ) ); ?>
+<?php $unique_id = esc_attr( twentyseventeen_unique_id( 'search-form-' ) ); ?>
 
 <form role="search" method="get" class="search-form" action="<?php echo esc_url( home_url( '/' ) ); ?>">
 	<label for="<?php echo $unique_id; ?>">
diff --git a/wp-includes/version.php b/wp-includes/version.php
index ae405e1157..b5c1d454a6 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0.3-alpha-44407';
+$wp_version = '5.0.3-alpha-44409';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.