diff --git a/wp-includes/blocks/search.php b/wp-includes/blocks/search.php
index 67bc90ff35..5face0b929 100644
--- a/wp-includes/blocks/search.php
+++ b/wp-includes/blocks/search.php
@@ -34,7 +34,7 @@ function render_block_core_search( $attributes ) {
 	}
 
 	$input_markup = sprintf(
-		'<input type="search" id="%s" class="wp-block-search__input" name="s" value="%s" placeholder="%s" />',
+		'<input type="search" id="%s" class="wp-block-search__input" name="s" value="%s" placeholder="%s" required />',
 		$input_id,
 		esc_attr( get_search_query() ),
 		esc_attr( $attributes['placeholder'] )
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 7fd5e3e23d..853dfdd0e4 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.4-alpha-47199';
+$wp_version = '5.4-alpha-47200';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.