This is release 1.66.0 (gladiator) of gRPC Core.

For gRPC documentation, see grpc.io. For previous releases, see Releases.

This release contains refinements, improvements, and bug fixes, with highlights listed below.

Core

• [Python Otel] Manage call tracer life cycle use call arena. (v1.66.x backport). (#37479)
• [BoringSSL] Update third_party/boringssl-with-bazel. (#37223)
• [Dep] Upgrading Protobuf to v27.2. (#36753)
• [Gpr_To_Absl_Logging] Fixing bugs . (#36961)
• [chttp2] don't access endpoint in transport ops if it's already been destroyed. (#36921)

C++

• [OTel C++] Fix race when adding and removing callbacks (#37485). (#37508)
• [RlsLB] Fix Deadlock (#37459). (#37502)

Python

• [Python Distrib] Change warning to RuntimeError for version incompatibility (v1.66.x backport). (#37477)
• Fix issues/36613. (#37022)
• [fix] updated invocation_metadata return type hint. (#36894)
• [Release] Add warning about PyPi latest version not necessarily matching Github latest version. (#36965)

Ruby

• [ruby] Update google-protobuf dep to allow 3.x and 4.x versions. (#36982)
• [ruby] improve the way completion queue pluck operations handle signals and process shutdown. (#36903)