diff --git a/wp-includes/class-wp-query.php b/wp-includes/class-wp-query.php
index 8afad87ec3..bdfce5e52c 100644
--- a/wp-includes/class-wp-query.php
+++ b/wp-includes/class-wp-query.php
@@ -1461,7 +1461,7 @@ class WP_Query {
 
 		foreach ( $q['search_terms'] as $term ) {
 			// If there is an $exclusion_prefix, terms prefixed with it should be excluded.
-			$exclude = $exclusion_prefix && ( substr( $term, 0, 1 ) === $exclusion_prefix );
+			$exclude = $exclusion_prefix && str_starts_with( $term, $exclusion_prefix );
 			if ( $exclude ) {
 				$like_op  = 'NOT LIKE';
 				$andor_op = 'AND';
diff --git a/wp-includes/deprecated.php b/wp-includes/deprecated.php
index cac1126dbe..750260ab56 100644
--- a/wp-includes/deprecated.php
+++ b/wp-includes/deprecated.php
@@ -947,7 +947,7 @@ function get_links($category = -1, $before = '', $after = '<br />', $between = '
 	_deprecated_function( __FUNCTION__, '2.1.0', 'get_bookmarks()' );
 
 	$order = 'ASC';
-	if ( substr($orderby, 0, 1) === '_' ) {
+	if ( str_starts_with($orderby, '_') ) {
 		$order = 'DESC';
 		$orderby = substr($orderby, 1);
 	}
diff --git a/wp-includes/link-template.php b/wp-includes/link-template.php
index 16c9da2d3b..2fe4483a7a 100644
--- a/wp-includes/link-template.php
+++ b/wp-includes/link-template.php
@@ -3891,7 +3891,7 @@ function set_url_scheme( $url, $scheme = null ) {
 	}
 
 	$url = trim( $url );
-	if ( substr( $url, 0, 2 ) === '//' ) {
+	if ( str_starts_with( $url, '//' ) ) {
 		$url = 'http:' . $url;
 	}
 
diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index bf62d0c127..3a4dd3115d 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -401,13 +401,12 @@ function is_email_address_unsafe( $user_email ) {
 				continue;
 			}
 
-			if ( $email_domain == $banned_domain ) {
+			if ( $email_domain === $banned_domain ) {
 				$is_email_address_unsafe = true;
 				break;
 			}
 
-			$dotted_domain = ".$banned_domain";
-			if ( substr( $normalized_email, -strlen( $dotted_domain ) ) === $dotted_domain ) {
+			if ( str_ends_with( $normalized_email, ".$banned_domain" ) ) {
 				$is_email_address_unsafe = true;
 				break;
 			}
diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
index 98c0a1bb64..d1f91b1e20 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
@@ -1137,7 +1137,7 @@ class WP_REST_Attachments_Controller extends WP_REST_Posts_Controller {
 			$filename = trim( $attributes['filename'] );
 
 			// Unquote quoted filename, but after trimming.
-			if ( substr( $filename, 0, 1 ) === '"' && substr( $filename, -1, 1 ) === '"' ) {
+			if ( str_starts_with( $filename, '"' ) && str_ends_with( $filename, '"' ) ) {
 				$filename = substr( $filename, 1, -1 );
 			}
 		}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index b11ed29d98..04ceb76707 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3-alpha-56018';
+$wp_version = '6.3-alpha-56019';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.