diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 3f7d9fe0e23..dddddf3ff77 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -158,6 +158,10 @@ API Changes
 
 * GITHUB#12718: Make IndexSearcher#getSlices final as it is not expected to be overridden (Luca Cavanna)
 
+* GITHUB#12427: Automata#makeStringUnion #makeBinaryStringUnion now accept Iterable<BytesRef> instead of
+  Collection<BytesRef>. They also now explicitly throw IllegalArgumentException if input data is not properly sorted
+  instead of relying on assert. (Shubham Chaudhary)
+
 New Features
 ---------------------