diff --git a/NEWS b/NEWS
index 0180f5b3478..683e7d906a8 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,8 @@ PHP                                                                        NEWS
 
 - Standard:
   . Fixed bug GH-16649 (UAF during array_splice). (alexandre-daubois)
+  . Passing integers outside the interval [0, 255] to chr() is now deprecated.
+    (Girgias)
 
 14 Aug 2025, PHP 8.5.0beta1
 
diff --git a/UPGRADING b/UPGRADING
index e586933fd93..16cb0c4e3ce 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -423,6 +423,9 @@ PHP 8.5 UPGRADE NOTES
     opened directory has been deprecated. Provide the last opened directory
     explicitly instead.
     RFC: https://wiki.php.net/rfc/deprecations_php_8_5#deprecate_passing_null_to_readdir_rewinddir_and_closedir
+  . Passing integers outside the interval [0, 255] to chr() is now deprecated.
+    This is because a byte can only hold a value within this interval.
+    RFC: https://wiki.php.net/rfc/deprecations_php_8_5#deprecate_passing_integers_outside_the_interval_0_255_to_chr
 
 - XML:
   . The xml_parser_free() function has been deprecated, as XMLParser objects