Update CHANGES.txt
diff --git a/CHANGES.txt b/CHANGES.txt
index f614602..343f512 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,37 @@
+Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
+ C++
+ * Better Smaller ByteSizeLong
+ * Introduce event filters for inject_field_listener_events
+ * Reduce memory usage of DescriptorPool
+ * For lazy fields copy serialized form when allowed.
+ * Re-introduce the InlinedStringField class
+ * v2 access listener
+ * Reduce padding in the proto's ExtensionRegistry map.
+ * GetExtension performance optimizations
+ * Make tracker a static variable rather than call static functions
+ * Support extensions in field access listener
+ * Annotate MergeFrom for field access listener
+ * Fix incomplete types for field access listener
+ * Add map_entry/new_map_entry to SpecificField in MessageDifferencer. They
+ record the map items which are different in MessageDifferencer's reporter.
+ * Reduce binary size due to fieldless proto messages
+ * TextFormat: ParseInfoTree supports getting field end location in addition to
+ start.
+ * Fix repeated enum extension size in field listener
+ * Enable Any Text Expansion for Descriptors::DebugString()
+ * Switch from int{8,16,32,64} to int{8,16,32,64}_t
+
+ Java
+ * Optimized FieldDescriptor.valueOf() to avoid array copying.
+ * Removing deprecated TimeUtil class.
+ * Add Durations.parseUnchecked(String) and Timestamps.parseUnchecked(String)
+ * FieldMaskUtil: Add convenience method to mask the fields out of a given proto.
+
+ JavaScript
+ * Optimize binary parsing of repeated float64
+ * Fix for optimization when reading doubles from binary wire format
+ * Replace toArray implementation with toJSON.
+
2021-06-04 version 3.17.3 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
C++
* Introduce FieldAccessListener.
