diff --git a/appendices/migration85/new-features.xml b/appendices/migration85/new-features.xml
index 5f2424d70af2..9acd268ef54b 100644
--- a/appendices/migration85/new-features.xml
+++ b/appendices/migration85/new-features.xml
@@ -68,7 +68,7 @@ print $result . PHP_EOL;  // Prints "11"
 
 #[\NoDiscard]
 function concat(string $a, string $b): string {
-     return a + b;
+     return $a . $b;
 }
 
 // Warning: The return value of function concat() should either be used or