[Announcement] Protocol Buffers Version v30.0 is Released!

[Jie Luo]

This version includes breaking changes to C++, Objective-C, Python, Rust:

• [C++] Remove deprecated APIs. 

• [C++] Remove CMake submodule support in favor of fetched or installed dependencies. 

• [C++] Prohibit using Bazel+MSVC to build protobuf 

• [C++] Strip ctype from options in C++ 

• [C++] Remove MutableRepeatedFieldRef::Reserve() in reflection

• [C++] Upgrade return type of several string returning functions to absl::string_view. 

• [C++] Flip default behavior for handling cmake dependencies. 

• [C++] Add ASAN poisoning after clearing oneof messages on arena. 

• [Objective-C] Remove legacy WKT headers.

• [Objective-C] Upgrade return type of several string returning functions to absl::string_view. 

• [Python] Remove deprecated APIs

• [Python] Upgrade return type of several string returning functions to absl::string_view. 

• [Python] Fix closed enum validation under editions 

• [Python] Python setdefault behavior change for map field.

• [Python] Python nested message class qualname now contains the outer message name. 

You can view the release and complete release notes on [GitHub](https://github.com/protocolbuffers/protobuf/releases/tag/v30.0) and additional information on our News page.
If you experience any issues with the release, please file a bug or post on the Protocol Buffers forum.

[Sandy Zhang]

Clarification that this version actually includes breaking changes to C++, Objective-C, and Python.

See https://github.com/protocolbuffers/protobuf/releases/tag/v30.0 for the actual set of breaking changes and other changes in this release.