1 files changed, 3 insertions, 0 deletions
diff --git a/NEWS b/NEWS
index 320ed6e563..2b9e1e6b8d 100644
--- a/NEWS
+++ b/NEWS
@@ -527,6 +527,9 @@ StringScanner::
   * Synchronizer
   * ThreadsWait
 
+Proc::
+  * Proc#to_s format was changed. [Feature #16101]
+
 === Stdlib compatibility issues (excluding feature bug fixes)
 
 pathname::