C++
* Fix warnings raised by clang 11 (8664)
* Make StringPiece constructible from std::string_view (8707)
* Add missing capability attributes for LLVM 12 (8714)
* Stop using std::iterator (deprecated in C++17). (8741)
* Move field_access_listener from libprotobuf-lite to libprotobuf (8775)
* Fix 7047 Safely handle setlocale (8735)
* Remove deprecated version of SetTotalBytesLimit() (8794)
* Support arena allocation of google::protobuf::AnyMetadata (8758)
* Fix undefined symbol error around SharedCtor() (8827)
* Fix default value of enum(int) in json_util with proto2 (8835)
* 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
* Fix errorprone conflict (8723)
* Removing deprecated TimeUtil class. (8749)
* 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.
PHP
* Migrate PHP & Ruby to ABSL wyhash (8854)
* Added support for PHP 8.1 (currently in RC1) to the C extension (8964)
* Fixed PHP SEGV when constructing messages from a destructor. (8969)
Ruby
* Move DSL implementation from C to pure Ruby (8850)
* Fixed a memory bug with RepeatedField+. (8970)
Python
* Drops support for 2.7 and 3.5.
Other
* [csharp] ByteString.CreateCodedInput should use ArraySegment offset and count (8740)
* [ObjC] Add support for using the proto package to prefix symbols. (8760)
* field_presence.md: fix Go example (8788)