diff --git a/BUILD b/BUILD
index 9dc049fd288..1f1d9affc34 100644
--- a/BUILD
+++ b/BUILD
@@ -200,8 +200,6 @@ GRPCXX_PUBLIC_HDRS = [
     "include/grpc++/impl/server_builder_plugin.h",
     "include/grpc++/impl/server_initializer.h",
     "include/grpc++/impl/service_type.h",
-    "include/grpc++/impl/sync_cxx11.h",
-    "include/grpc++/impl/sync_no_cxx11.h",
     "include/grpc++/security/auth_context.h",
     "include/grpc++/resource_quota.h",
     "include/grpc++/security/auth_metadata_processor.h",
@@ -256,8 +254,6 @@ GRPCXX_PUBLIC_HDRS = [
     "include/grpcpp/impl/server_initializer.h",
     "include/grpcpp/impl/server_initializer_impl.h",
     "include/grpcpp/impl/service_type.h",
-    "include/grpcpp/impl/sync_cxx11.h",
-    "include/grpcpp/impl/sync_no_cxx11.h",
     "include/grpcpp/resource_quota.h",
     "include/grpcpp/resource_quota_impl.h",
     "include/grpcpp/security/auth_context.h",
@@ -750,6 +746,7 @@ grpc_cc_library(
         "src/core/lib/iomgr/iomgr_internal.cc",
         "src/core/lib/iomgr/iomgr_posix.cc",
         "src/core/lib/iomgr/iomgr_posix_cfstream.cc",
+        "src/core/lib/iomgr/iomgr_uv.cc",
         "src/core/lib/iomgr/iomgr_windows.cc",
         "src/core/lib/iomgr/is_epollexclusive_available.cc",
         "src/core/lib/iomgr/load_file.cc",
@@ -773,6 +770,7 @@ grpc_cc_library(
         "src/core/lib/iomgr/socket_utils_common_posix.cc",
         "src/core/lib/iomgr/socket_utils_linux.cc",
         "src/core/lib/iomgr/socket_utils_posix.cc",
+        "src/core/lib/iomgr/socket_utils_uv.cc",
         "src/core/lib/iomgr/socket_utils_windows.cc",
         "src/core/lib/iomgr/socket_windows.cc",
         "src/core/lib/iomgr/tcp_client.cc",
@@ -992,6 +990,7 @@ grpc_cc_library(
     public_hdrs = GRPC_PUBLIC_HDRS,
     use_cfstream = True,
     deps = [
+        "eventmanager_libuv",
         "gpr_base",
         "grpc_codegen",
         "grpc_trace",
diff --git a/BUILDING.md b/BUILDING.md
index 9addae90fc7..a113700729a 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -72,13 +72,13 @@ To prepare for cmake + Microsoft Visual C++ compiler build
 # Clone the repository (including submodules)
 
 Before building, you need to clone the gRPC github repository and download submodules containing source code
-for gRPC's dependencies (that's done by the `submodule` command or `--recursive` flag). The following commands will clone the gRPC
-repository at the latest stable version.
+for gRPC's dependencies (that's done by the `submodule` command or `--recursive` flag). Use following commands
+to clone the gRPC repository at the [latest stable release tag](https://github.com/grpc/grpc/releases)
 
 ## Unix
 
 ```sh
- $ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+ $ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
  $ cd grpc
  $ git submodule update --init
  ```
@@ -86,10 +86,9 @@ repository at the latest stable version.
 ## Windows
 
 ```
-> @rem You can also do just "git clone --recursive -b THE_BRANCH_YOU_WANT https://github.com/grpc/grpc"
-> powershell git clone --recursive -b ((New-Object System.Net.WebClient).DownloadString(\"https://grpc.io/release\").Trim()) https://github.com/grpc/grpc
+> git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 > cd grpc
-> @rem To update submodules at later time, run "git submodule update --init"
+> git submodule update --init
 ```
 
 NOTE: The `bazel` build tool uses a different model for dependencies. You only need to worry about downloading submodules if you're building
diff --git a/Makefile b/Makefile
index 30384b57a98..3750bdf78e7 100644
--- a/Makefile
+++ b/Makefile
@@ -3944,7 +3944,7 @@ PUBLIC_HEADERS_C += \
 LIBGPR_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGPR_SRC))))
 
 
-$(LIBDIR)/$(CONFIG)/libgpr.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(LIBGPR_OBJS) 
+$(LIBDIR)/$(CONFIG)/libgpr.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBGPR_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgpr.a
@@ -5479,7 +5479,7 @@ PUBLIC_HEADERS_C += \
 LIBGRPC_TEST_UTIL_UNSECURE_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPC_TEST_UTIL_UNSECURE_SRC))))
 
 
-$(LIBDIR)/$(CONFIG)/libgrpc_test_util_unsecure.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(LIBGRPC_TEST_UTIL_UNSECURE_OBJS) 
+$(LIBDIR)/$(CONFIG)/libgrpc_test_util_unsecure.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBGRPC_TEST_UTIL_UNSECURE_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgrpc_test_util_unsecure.a
@@ -5846,7 +5846,7 @@ PUBLIC_HEADERS_C += \
 LIBGRPC_UNSECURE_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPC_UNSECURE_SRC))))
 
 
-$(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(LIBGRPC_UNSECURE_OBJS)  $(LIBGPR_OBJS)  $(LIBGRPC_ABSEIL_OBJS)  $(ZLIB_MERGE_OBJS)  $(CARES_MERGE_OBJS)  $(ADDRESS_SORTING_MERGE_OBJS)  $(UPB_MERGE_OBJS) 
+$(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBGRPC_UNSECURE_OBJS)  $(LIBGPR_OBJS)  $(LIBGRPC_ABSEIL_OBJS)  $(ZLIB_MERGE_OBJS)  $(CARES_MERGE_OBJS)  $(ADDRESS_SORTING_MERGE_OBJS)  $(UPB_MERGE_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a
@@ -7493,7 +7493,7 @@ $(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)grpc++_unsecure$(SHARED_VERSION_CPP).$(SHARE
 
 else
 
-$(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBGRPC++_UNSECURE_OBJS)  $(LIBGPR_OBJS)  $(LIBGRPC_ABSEIL_OBJS)  $(ZLIB_MERGE_OBJS)  $(CARES_MERGE_OBJS)  $(ADDRESS_SORTING_MERGE_OBJS)  $(UPB_MERGE_OBJS) 
+$(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBGRPC++_UNSECURE_OBJS)  $(LIBGPR_OBJS)  $(LIBGRPC_ABSEIL_OBJS)  $(ZLIB_MERGE_OBJS)  $(CARES_MERGE_OBJS)  $(ADDRESS_SORTING_MERGE_OBJS)  $(UPB_MERGE_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a
@@ -7665,7 +7665,7 @@ $(LIBDIR)/$(CONFIG)/libgrpc_plugin_support.a: protobuf_dep_error
 
 else
 
-$(LIBDIR)/$(CONFIG)/libgrpc_plugin_support.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBGRPC_PLUGIN_SUPPORT_OBJS) 
+$(LIBDIR)/$(CONFIG)/libgrpc_plugin_support.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBGRPC_PLUGIN_SUPPORT_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgrpc_plugin_support.a
@@ -8480,7 +8480,7 @@ $(LIBBORINGSSL_OBJS): CPPFLAGS += -Ithird_party/boringssl-with-bazel/src/include
 $(LIBBORINGSSL_OBJS): CXXFLAGS += -fno-exceptions
 $(LIBBORINGSSL_OBJS): CFLAGS += -g
 
-$(LIBDIR)/$(CONFIG)/libboringssl.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(LIBBORINGSSL_OBJS) 
+$(LIBDIR)/$(CONFIG)/libboringssl.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBBORINGSSL_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libboringssl.a
@@ -8520,7 +8520,7 @@ $(LIBDIR)/$(CONFIG)/libboringssl_test_util.a: protobuf_dep_error
 
 else
 
-$(LIBDIR)/$(CONFIG)/libboringssl_test_util.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBBORINGSSL_TEST_UTIL_OBJS) 
+$(LIBDIR)/$(CONFIG)/libboringssl_test_util.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBBORINGSSL_TEST_UTIL_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libboringssl_test_util.a
@@ -8575,7 +8575,7 @@ $(LIBDIR)/$(CONFIG)/libbenchmark.a: protobuf_dep_error
 
 else
 
-$(LIBDIR)/$(CONFIG)/libbenchmark.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBBENCHMARK_OBJS) 
+$(LIBDIR)/$(CONFIG)/libbenchmark.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(PROTOBUF_DEP) $(LIBBENCHMARK_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libbenchmark.a
@@ -8607,18 +8607,7 @@ PUBLIC_HEADERS_C += \
 LIBUPB_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBUPB_SRC))))
 
 
-ifeq ($(NO_SECURE),true)
-
-# You can't build secure libraries if you don't have OpenSSL.
-
-$(LIBDIR)/$(CONFIG)/libupb.a: openssl_dep_error
-
-$(LIBDIR)/$(CONFIG)/$(SHARED_PREFIX)upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): openssl_dep_error
-
-else
-
-
-$(LIBDIR)/$(CONFIG)/libupb.a: $(ZLIB_DEP) $(OPENSSL_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBUPB_OBJS) 
+$(LIBDIR)/$(CONFIG)/libupb.a:  $(LIBUPB_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libupb.a
@@ -8630,12 +8619,12 @@ endif
 
 
 ifeq ($(SYSTEM),MINGW32)
-$(LIBDIR)/$(CONFIG)/upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBUPB_OBJS)  $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP) $(OPENSSL_DEP)
+$(LIBDIR)/$(CONFIG)/upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBUPB_OBJS)  $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)
 	$(E) "[LD]      Linking $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,--output-def=$(LIBDIR)/$(CONFIG)/upb$(SHARED_VERSION_CORE).def -Wl,--out-implib=$(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE)-dll.a -o $(LIBDIR)/$(CONFIG)/upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBUPB_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-$(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBUPB_OBJS)  $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP) $(OPENSSL_DEP)
+$(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBUPB_OBJS)  $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)
 	$(E) "[LD]      Linking $@"
 	$(Q) mkdir -p `dirname $@`
 ifeq ($(SYSTEM),Darwin)
@@ -8647,13 +8636,9 @@ else
 endif
 endif
 
-endif
-
-ifneq ($(NO_SECURE),true)
 ifneq ($(NO_DEPS),true)
 -include $(LIBUPB_OBJS:.o=.dep)
 endif
-endif
 
 
 LIBZ_SRC = \
@@ -9064,7 +9049,7 @@ PUBLIC_HEADERS_C += \
 LIBEND2END_NOSEC_TESTS_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBEND2END_NOSEC_TESTS_SRC))))
 
 
-$(LIBDIR)/$(CONFIG)/libend2end_nosec_tests.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(LIBGRPC_ABSEIL_DEP)  $(LIBEND2END_NOSEC_TESTS_OBJS) 
+$(LIBDIR)/$(CONFIG)/libend2end_nosec_tests.a: $(ZLIB_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBEND2END_NOSEC_TESTS_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libend2end_nosec_tests.a
@@ -9118,17 +9103,7 @@ LIBGRPC_ABSEIL_SRC = \
 LIBGRPC_ABSEIL_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPC_ABSEIL_SRC))))
 
 
-ifeq ($(NO_SECURE),true)
-
-# You can't build secure libraries if you don't have OpenSSL.
-
-$(LIBDIR)/$(CONFIG)/libgrpc_abseil.a: openssl_dep_error
-
-
-else
-
-
-$(LIBDIR)/$(CONFIG)/libgrpc_abseil.a: $(ZLIB_DEP) $(OPENSSL_DEP) $(CARES_DEP) $(ADDRESS_SORTING_DEP) $(UPB_DEP) $(GRPC_ABSEIL_DEP)  $(LIBGRPC_ABSEIL_OBJS) 
+$(LIBDIR)/$(CONFIG)/libgrpc_abseil.a:  $(LIBGRPC_ABSEIL_OBJS) 
 	$(E) "[AR]      Creating $@"
 	$(Q) mkdir -p `dirname $@`
 	$(Q) rm -f $(LIBDIR)/$(CONFIG)/libgrpc_abseil.a
@@ -9140,13 +9115,9 @@ endif
 
 
 
-endif
-
-ifneq ($(NO_SECURE),true)
 ifneq ($(NO_DEPS),true)
 -include $(LIBGRPC_ABSEIL_OBJS:.o=.dep)
 endif
-endif
 
 
 # All of the test targets, and protoc plugins
@@ -23548,40 +23519,6 @@ test/cpp/util/string_ref_helper.cc: $(OPENSSL_DEP)
 test/cpp/util/subprocess.cc: $(OPENSSL_DEP)
 test/cpp/util/test_config_cc.cc: $(OPENSSL_DEP)
 test/cpp/util/test_credentials_provider.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/dynamic_annotations.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/cycleclock.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/raw_logging.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/spinlock.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/spinlock_wait.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/sysinfo.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/thread_identity.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/throw_delegate.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/internal/unscaledcycleclock.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/base/log_severity.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/numeric/int128.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/ascii.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/charconv.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/escaping.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/internal/charconv_bigint.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/internal/charconv_parse.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/internal/escaping.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/internal/memutil.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/internal/ostringstream.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/internal/utf8.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/match.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/numbers.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/str_cat.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/str_replace.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/str_split.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/string_view.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/strings/substitute.cc: $(OPENSSL_DEP)
-third_party/abseil-cpp/absl/types/bad_optional_access.cc: $(OPENSSL_DEP)
-third_party/upb/upb/decode.c: $(OPENSSL_DEP)
-third_party/upb/upb/encode.c: $(OPENSSL_DEP)
-third_party/upb/upb/msg.c: $(OPENSSL_DEP)
-third_party/upb/upb/port.c: $(OPENSSL_DEP)
-third_party/upb/upb/table.c: $(OPENSSL_DEP)
-third_party/upb/upb/upb.c: $(OPENSSL_DEP)
 endif
 
 .PHONY: all strip tools dep_error openssl_dep_error openssl_dep_message git_update stop buildtests buildtests_c buildtests_cxx test test_c test_cxx install install_c install_cxx install-headers install-headers_c install-headers_cxx install-shared install-shared_c install-shared_cxx install-static install-static_c install-static_cxx strip strip-shared strip-static strip_c strip-shared_c strip-static_c strip_cxx strip-shared_cxx strip-static_cxx dep_c dep_cxx bins_dep_c bins_dep_cxx clean
diff --git a/README.md b/README.md
index ad27d0bd3b7..d3eee331088 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ Sometimes things go wrong. Please check out the [Troubleshooting guide](TROUBLES
 
 # Performance 
 
-See the [Performance dashboard](http://performance-dot-grpc-testing.appspot.com/explore?dashboard=5636470266134528) for performance numbers of the latest released version.
+See the [Performance dashboard](https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5652536396611584) for performance numbers of master branch daily builds.
 
 # Concepts
 
diff --git a/examples/cpp/compression/README.md b/examples/cpp/compression/README.md
index 13988f2c0c5..6ba42498ab2 100644
--- a/examples/cpp/compression/README.md
+++ b/examples/cpp/compression/README.md
@@ -5,11 +5,11 @@ Make sure you have run the [hello world example](../helloworld) or understood th
 
 ### Get the tutorial source code
 
-The example code for this and our other examples lives in the `examples` directory. Clone this repository to your local machine by running the following command:
+The example code for this and our other examples lives in the `examples` directory. Clone this repository at the [latest stable release tag](https://github.com/grpc/grpc/releases) to your local machine  by running the following command:
 
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 ```
 
 Change your current directory to examples/cpp/compression
diff --git a/examples/cpp/helloworld/README.md b/examples/cpp/helloworld/README.md
index 584c46ec40d..71718645645 100644
--- a/examples/cpp/helloworld/README.md
+++ b/examples/cpp/helloworld/README.md
@@ -7,12 +7,12 @@ Make sure you have installed gRPC on your system. Follow the
 ### Get the tutorial source code
 
 The example code for this and our other examples lives in the `examples`
-directory. Clone this repository to your local machine by running the
-following command:
+directory. Clone this repository at the [latest stable release tag](https://github.com/grpc/grpc/releases)
+to your local machine by running the following command:
 
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 ```
 
 Change your current directory to examples/cpp/helloworld
diff --git a/examples/cpp/load_balancing/README.md b/examples/cpp/load_balancing/README.md
index f48aca5307f..70c6c2a3491 100644
--- a/examples/cpp/load_balancing/README.md
+++ b/examples/cpp/load_balancing/README.md
@@ -5,11 +5,12 @@ Make sure you have run the [hello world example](../helloworld) or understood th
 
 ### Get the tutorial source code
 
-The example code for this and our other examples lives in the `examples` directory. Clone this repository to your local machine by running the following command:
+The example code for this and our other examples lives in the `examples` directory. Clone this repository 
+at the [latest stable release tag](https://github.com/grpc/grpc/releases) to your local machine by running the following command:
 
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 ```
 
 Change your current directory to examples/cpp/load_balancing
diff --git a/examples/cpp/metadata/README.md b/examples/cpp/metadata/README.md
index 96ad3d19bdb..334009bdfa7 100644
--- a/examples/cpp/metadata/README.md
+++ b/examples/cpp/metadata/README.md
@@ -10,9 +10,10 @@ https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md, with the
 exception of binary headers, which don't have to be base64 encoded.
 
 ### Get the tutorial source code
- The example code for this and our other examples lives in the `examples` directory. Clone this repository to your local machine by running the following command:
+ The example code for this and our other examples lives in the `examples` directory. Clone this repository 
+ at the [latest stable release tag](https://github.com/grpc/grpc/releases) to your local machine by running the following command:
  ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 ```
  Change your current directory to examples/cpp/metadata
  ```sh
diff --git a/examples/node/README.md b/examples/node/README.md
index f94dcca0f14..0264e9d66b7 100644
--- a/examples/node/README.md
+++ b/examples/node/README.md
@@ -12,7 +12,7 @@ INSTALL
    ```sh
    $ # Get the gRPC repository
    $ export REPO_ROOT=grpc # REPO root can be any directory of your choice
-   $ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc $REPO_ROOT
+   $ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc $REPO_ROOT
    $ cd $REPO_ROOT
 
    $ cd examples/node
diff --git a/examples/objective-c/helloworld/README.md b/examples/objective-c/helloworld/README.md
index 7a7516a3dca..c57e07ca931 100644
--- a/examples/objective-c/helloworld/README.md
+++ b/examples/objective-c/helloworld/README.md
@@ -18,11 +18,11 @@ Here's how to build and run the Objective-C implementation of the [Hello World](
 example used in [Getting started](https://github.com/grpc/grpc/tree/master/examples).
 
 The example code for this and our other examples lives in the `examples` directory. Clone
-this repository to your local machine by running the following commands:
+this repository at the [latest stable release tag](https://github.com/grpc/grpc/releases) to your local machine by running the following commands:
 
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 $ cd grpc
 $ git submodule update --init
 ```
diff --git a/examples/php/README.md b/examples/php/README.md
index cb0b111e8c4..75b9e6fb829 100644
--- a/examples/php/README.md
+++ b/examples/php/README.md
@@ -16,7 +16,7 @@ This requires `php` >= 5.5, `pecl`, `composer`
  - Install the `protoc` compiler plugin `grpc_php_plugin`
 
    ```sh
-   $ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+   $ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
    $ cd grpc
    $ make grpc_php_plugin
    ```
diff --git a/include/grpc++/impl/sync_cxx11.h b/include/grpc++/impl/sync_cxx11.h
deleted file mode 100644
index 8bcfb2ce818..00000000000
--- a/include/grpc++/impl/sync_cxx11.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- *
- * Copyright 2018 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-// DEPRECATED: The headers in include/grpc++ are deprecated. Please include the
-// headers in include/grpcpp instead. This header exists only for backwards
-// compatibility.
-
-#ifndef GRPCXX_IMPL_SYNC_CXX11_H
-#define GRPCXX_IMPL_SYNC_CXX11_H
-
-#include <grpcpp/impl/sync_cxx11.h>
-
-#endif  // GRPCXX_IMPL_SYNC_CXX11_H
diff --git a/include/grpc++/impl/sync_no_cxx11.h b/include/grpc++/impl/sync_no_cxx11.h
deleted file mode 100644
index 5264567387a..00000000000
--- a/include/grpc++/impl/sync_no_cxx11.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- *
- * Copyright 2018 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-// DEPRECATED: The headers in include/grpc++ are deprecated. Please include the
-// headers in include/grpcpp instead. This header exists only for backwards
-// compatibility.
-
-#ifndef GRPCXX_IMPL_SYNC_NO_CXX11_H
-#define GRPCXX_IMPL_SYNC_NO_CXX11_H
-
-#include <grpcpp/impl/sync_no_cxx11.h>
-
-#endif  // GRPCXX_IMPL_SYNC_NO_CXX11_H
diff --git a/include/grpcpp/impl/codegen/completion_queue_impl.h b/include/grpcpp/impl/codegen/completion_queue_impl.h
index 502edfd9f15..c65b12197dc 100644
--- a/include/grpcpp/impl/codegen/completion_queue_impl.h
+++ b/include/grpcpp/impl/codegen/completion_queue_impl.h
@@ -387,12 +387,14 @@ class CompletionQueue : private ::grpc::GrpcLibraryCodegen {
   }
 
   void RegisterServer(const Server* server) {
+    (void)server;
 #ifndef NDEBUG
     grpc::internal::MutexLock l(&server_list_mutex_);
     server_list_.push_back(server);
 #endif
   }
   void UnregisterServer(const Server* server) {
+    (void)server;
 #ifndef NDEBUG
     grpc::internal::MutexLock l(&server_list_mutex_);
     server_list_.remove(server);
diff --git a/include/grpcpp/impl/codegen/time.h b/include/grpcpp/impl/codegen/time.h
index b3521722e9e..a08e9cbe189 100644
--- a/include/grpcpp/impl/codegen/time.h
+++ b/include/grpcpp/impl/codegen/time.h
@@ -39,14 +39,12 @@ namespace grpc {
 template <typename T>
 class TimePoint {
  public:
-  TimePoint(const T& /*time*/) { you_need_a_specialization_of_TimePoint(); }
-  gpr_timespec raw_time() {
-    gpr_timespec t;
-    return t;
-  }
-
- private:
-  void you_need_a_specialization_of_TimePoint();
+  // If you see the error with methods below, you may need either
+  // i) using the existing types having a conversion class such as
+  // gpr_timespec and std::chrono::system_clock::time_point or
+  // ii) writing a new TimePoint<YourType> to address your case.
+  TimePoint(const T& /*time*/) = delete;
+  gpr_timespec raw_time() = delete;
 };
 
 template <>
diff --git a/include/grpcpp/impl/sync_cxx11.h b/include/grpcpp/impl/sync_cxx11.h
deleted file mode 100644
index 76dcfe391c9..00000000000
--- a/include/grpcpp/impl/sync_cxx11.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#ifndef GRPCPP_IMPL_SYNC_CXX11_H
-#define GRPCPP_IMPL_SYNC_CXX11_H
-
-#include <grpcpp/impl/codegen/sync_cxx11.h>
-
-#endif  // GRPCPP_IMPL_SYNC_CXX11_H
diff --git a/include/grpcpp/impl/sync_no_cxx11.h b/include/grpcpp/impl/sync_no_cxx11.h
deleted file mode 100644
index cc2d4f104cf..00000000000
--- a/include/grpcpp/impl/sync_no_cxx11.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#ifndef GRPCPP_IMPL_SYNC_NO_CXX11_H
-#define GRPCPP_IMPL_SYNC_NO_CXX11_H
-
-#include <grpcpp/impl/codegen/sync_no_cxx11.h>
-
-#endif  // GRPCPP_IMPL_SYNC_NO_CXX11_H
diff --git a/src/abseil-cpp/gen_build_yaml.py b/src/abseil-cpp/gen_build_yaml.py
index 8a4657f0b3c..2f32a3e25c7 100755
--- a/src/abseil-cpp/gen_build_yaml.py
+++ b/src/abseil-cpp/gen_build_yaml.py
@@ -26,4 +26,5 @@ for build in builds:
     build['build'] = 'private'
     build['build_system'] = []
     build['language'] = 'c'
+    build['secure'] = False
 print(yaml.dump({'libs': builds}))
diff --git a/src/core/ext/filters/client_channel/xds/xds_client.cc b/src/core/ext/filters/client_channel/xds/xds_client.cc
index 1d6b86ad65e..f7f2c2c605b 100644
--- a/src/core/ext/filters/client_channel/xds/xds_client.cc
+++ b/src/core/ext/filters/client_channel/xds/xds_client.cc
@@ -1751,8 +1751,16 @@ XdsClient::~XdsClient() { GRPC_COMBINER_UNREF(combiner_, "xds_client"); }
 void XdsClient::Orphan() {
   shutting_down_ = true;
   chand_.reset();
-  cluster_map_.clear();
-  endpoint_map_.clear();
+  // We do not clear cluster_map_ and endpoint_map_ if the xds client was
+  // created by the XdsResolver because the maps contain refs for watchers which
+  // in turn hold refs to the loadbalancing policies. At this point, it is
+  // possible for ADS calls to be in progress. Unreffing the loadbalancing
+  // policies before those calls are done would lead to issues such as
+  // https://github.com/grpc/grpc/issues/20928.
+  if (service_config_watcher_ != nullptr) {
+    cluster_map_.clear();
+    endpoint_map_.clear();
+  }
   Unref(DEBUG_LOCATION, "XdsClient::Orphan()");
 }
 
@@ -1902,13 +1910,13 @@ void XdsClient::NotifyOnError(grpc_error* error) {
 
 void* XdsClient::ChannelArgCopy(void* p) {
   XdsClient* xds_client = static_cast<XdsClient*>(p);
-  xds_client->Ref().release();
+  xds_client->Ref(DEBUG_LOCATION, "channel arg").release();
   return p;
 }
 
 void XdsClient::ChannelArgDestroy(void* p) {
   XdsClient* xds_client = static_cast<XdsClient*>(p);
-  xds_client->Unref();
+  xds_client->Unref(DEBUG_LOCATION, "channel arg");
 }
 
 int XdsClient::ChannelArgCmp(void* p, void* q) { return GPR_ICMP(p, q); }
diff --git a/src/core/lib/iomgr/tcp_posix.cc b/src/core/lib/iomgr/tcp_posix.cc
index c96031183b3..bd0562bfa74 100644
--- a/src/core/lib/iomgr/tcp_posix.cc
+++ b/src/core/lib/iomgr/tcp_posix.cc
@@ -1385,7 +1385,8 @@ static bool do_tcp_flush_zerocopy(grpc_tcp* tcp, TcpZerocopySendRecord* record,
 
 static void UnrefMaybePutZerocopySendRecord(grpc_tcp* tcp,
                                             TcpZerocopySendRecord* record,
-                                            uint32_t seq, const char* tag) {
+                                            uint32_t seq,
+                                            const char* /* tag */) {
   if (record->Unref()) {
     tcp->tcp_zerocopy_send_ctx.PutSendRecord(record);
   }
diff --git a/src/core/lib/security/security_connector/local/local_security_connector.cc b/src/core/lib/security/security_connector/local/local_security_connector.cc
index 6fb770d7ade..f2e4e0c36d9 100644
--- a/src/core/lib/security/security_connector/local/local_security_connector.cc
+++ b/src/core/lib/security/security_connector/local/local_security_connector.cc
@@ -66,8 +66,7 @@ grpc_core::RefCountedPtr<grpc_auth_context> local_auth_context_create(
   return ctx;
 }
 
-void local_check_peer(grpc_security_connector* sc, tsi_peer peer,
-                      grpc_endpoint* ep,
+void local_check_peer(tsi_peer peer, grpc_endpoint* ep,
                       grpc_core::RefCountedPtr<grpc_auth_context>* auth_context,
                       grpc_closure* on_peer_checked,
                       grpc_local_connect_type type) {
@@ -178,7 +177,7 @@ class grpc_local_channel_security_connector final
                   grpc_closure* on_peer_checked) override {
     grpc_local_credentials* creds =
         reinterpret_cast<grpc_local_credentials*>(mutable_channel_creds());
-    local_check_peer(this, peer, ep, auth_context, on_peer_checked,
+    local_check_peer(peer, ep, auth_context, on_peer_checked,
                      creds->connect_type());
   }
 
@@ -227,7 +226,7 @@ class grpc_local_server_security_connector final
                   grpc_closure* on_peer_checked) override {
     grpc_local_server_credentials* creds =
         static_cast<grpc_local_server_credentials*>(mutable_server_creds());
-    local_check_peer(this, peer, ep, auth_context, on_peer_checked,
+    local_check_peer(peer, ep, auth_context, on_peer_checked,
                      creds->connect_type());
   }
 
diff --git a/src/core/tsi/alts/handshaker/alts_handshaker_client.cc b/src/core/tsi/alts/handshaker/alts_handshaker_client.cc
index ec17b962972..2592763e5a2 100644
--- a/src/core/tsi/alts/handshaker/alts_handshaker_client.cc
+++ b/src/core/tsi/alts/handshaker/alts_handshaker_client.cc
@@ -637,7 +637,7 @@ static void handshaker_client_shutdown(alts_handshaker_client* c) {
   }
 }
 
-static void handshaker_call_unref(void* arg, grpc_error* error) {
+static void handshaker_call_unref(void* arg, grpc_error* /* error */) {
   grpc_call* call = static_cast<grpc_call*>(arg);
   grpc_call_unref(call);
 }
diff --git a/src/core/tsi/alts/handshaker/alts_tsi_handshaker.cc b/src/core/tsi/alts/handshaker/alts_tsi_handshaker.cc
index b24ed1f24ab..0c700306d8f 100644
--- a/src/core/tsi/alts/handshaker/alts_tsi_handshaker.cc
+++ b/src/core/tsi/alts/handshaker/alts_tsi_handshaker.cc
@@ -430,7 +430,7 @@ struct alts_tsi_handshaker_continue_handshaker_next_args {
 };
 
 static void alts_tsi_handshaker_create_channel(void* arg,
-                                               grpc_error* unused_error) {
+                                               grpc_error* /* unused_error */) {
   alts_tsi_handshaker_continue_handshaker_next_args* next_args =
       static_cast<alts_tsi_handshaker_continue_handshaker_next_args*>(arg);
   alts_tsi_handshaker* handshaker = next_args->handshaker;
diff --git a/src/php/README.md b/src/php/README.md
index bea2e6f9290..f064ff0d698 100644
--- a/src/php/README.md
+++ b/src/php/README.md
@@ -47,10 +47,10 @@ You can download the pre-compiled `grpc.dll` extension from the PECL
 
 ### Build from source
 
-Clone this repository
+Clone this repository at the [latest stable release tag](https://github.com/grpc/grpc/releases)
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 ```
 
 #### Build and install the gRPC C core library
@@ -184,7 +184,7 @@ in the future.
 You can also just build the `grpc_php_plugin` by running:
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 $ cd grpc
 $ git submodule update --init
 $ make grpc_php_plugin
@@ -246,7 +246,7 @@ $ protoc -I=. echo.proto --php_out=. --grpc_out=. \
 You will need the source code to run tests
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc
 $ cd grpc
 $ git submodule update --init
 ```
diff --git a/src/python/grpcio/README.rst b/src/python/grpcio/README.rst
index c7c6aa497d5..9fde3878488 100644
--- a/src/python/grpcio/README.rst
+++ b/src/python/grpcio/README.rst
@@ -59,7 +59,7 @@ package named :code:`python-dev`).
 ::
 
   $ export REPO_ROOT=grpc  # REPO_ROOT can be any directory of your choice
-  $ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc $REPO_ROOT
+  $ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc $REPO_ROOT
   $ cd $REPO_ROOT
   $ git submodule update --init
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/aio/call.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/aio/call.pxd.pxi
index acee440e673..867245a6944 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/aio/call.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/aio/call.pxd.pxi
@@ -15,7 +15,7 @@
 
 cdef class _AioCall(GrpcCallWrapper):
     cdef:
-        AioChannel _channel
+        readonly AioChannel _channel
         list _references
         object _deadline
         list _done_callbacks
diff --git a/src/python/grpcio/grpc/experimental/aio/_channel.py b/src/python/grpcio/grpc/experimental/aio/_channel.py
index 7201aabcc73..cb4ed80339c 100644
--- a/src/python/grpcio/grpc/experimental/aio/_channel.py
+++ b/src/python/grpcio/grpc/experimental/aio/_channel.py
@@ -12,16 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Invocation-side implementation of gRPC Asyncio Python."""
+
 import asyncio
-from typing import Any, AsyncIterable, Optional, Sequence, AbstractSet
-from weakref import WeakSet
+import sys
+from typing import Any, AsyncIterable, Iterable, Optional, Sequence
 
-import logging
 import grpc
-from grpc import _common
+from grpc import _common, _compression, _grpcio_metadata
 from grpc._cython import cygrpc
-from grpc import _compression
-from grpc import _grpcio_metadata
 
 from . import _base_call
 from ._call import (StreamStreamCall, StreamUnaryCall, UnaryStreamCall,
@@ -35,6 +33,15 @@ from ._utils import _timeout_to_deadline
 _IMMUTABLE_EMPTY_TUPLE = tuple()
 _USER_AGENT = 'grpc-python-asyncio/{}'.format(_grpcio_metadata.__version__)
 
+if sys.version_info[1] < 7:
+
+    def _all_tasks() -> Iterable[asyncio.Task]:
+        return asyncio.Task.all_tasks()
+else:
+
+    def _all_tasks() -> Iterable[asyncio.Task]:
+        return asyncio.all_tasks()
+
 
 def _augment_channel_arguments(base_options: ChannelArgumentType,
                                compression: Optional[grpc.Compression]):
@@ -48,50 +55,12 @@ def _augment_channel_arguments(base_options: ChannelArgumentType,
                 ) + compression_channel_argument + user_agent_channel_argument
 
 
-_LOGGER = logging.getLogger(__name__)
-
-
-class _OngoingCalls:
-    """Internal class used for have visibility of the ongoing calls."""
-
-    _calls: AbstractSet[_base_call.RpcContext]
-
-    def __init__(self):
-        self._calls = WeakSet()
-
-    def _remove_call(self, call: _base_call.RpcContext):
-        try:
-            self._calls.remove(call)
-        except KeyError:
-            pass
-
-    @property
-    def calls(self) -> AbstractSet[_base_call.RpcContext]:
-        """Returns the set of ongoing calls."""
-        return self._calls
-
-    def size(self) -> int:
-        """Returns the number of ongoing calls."""
-        return len(self._calls)
-
-    def trace_call(self, call: _base_call.RpcContext):
-        """Adds and manages a new ongoing call."""
-        self._calls.add(call)
-        call.add_done_callback(self._remove_call)
-
-
 class _BaseMultiCallable:
     """Base class of all multi callable objects.
 
     Handles the initialization logic and stores common attributes.
     """
     _loop: asyncio.AbstractEventLoop
-    _channel: cygrpc.AioChannel
-    _ongoing_calls: _OngoingCalls
-    _method: bytes
-    _request_serializer: SerializingFunction
-    _response_deserializer: DeserializingFunction
-
     _channel: cygrpc.AioChannel
     _method: bytes
     _request_serializer: SerializingFunction
@@ -103,7 +72,6 @@ class _BaseMultiCallable:
     def __init__(
             self,
             channel: cygrpc.AioChannel,
-            ongoing_calls: _OngoingCalls,
             method: bytes,
             request_serializer: SerializingFunction,
             response_deserializer: DeserializingFunction,
@@ -112,7 +80,6 @@ class _BaseMultiCallable:
     ) -> None:
         self._loop = loop
         self._channel = channel
-        self._ongoing_calls = ongoing_calls
         self._method = method
         self._request_serializer = request_serializer
         self._response_deserializer = response_deserializer
@@ -170,7 +137,6 @@ class UnaryUnaryMultiCallable(_BaseMultiCallable):
                 self._request_serializer, self._response_deserializer,
                 self._loop)
 
-        self._ongoing_calls.trace_call(call)
         return call
 
 
@@ -213,7 +179,7 @@ class UnaryStreamMultiCallable(_BaseMultiCallable):
                                wait_for_ready, self._channel, self._method,
                                self._request_serializer,
                                self._response_deserializer, self._loop)
-        self._ongoing_calls.trace_call(call)
+
         return call
 
 
@@ -260,7 +226,7 @@ class StreamUnaryMultiCallable(_BaseMultiCallable):
                                credentials, wait_for_ready, self._channel,
                                self._method, self._request_serializer,
                                self._response_deserializer, self._loop)
-        self._ongoing_calls.trace_call(call)
+
         return call
 
 
@@ -307,7 +273,7 @@ class StreamStreamMultiCallable(_BaseMultiCallable):
                                 credentials, wait_for_ready, self._channel,
                                 self._method, self._request_serializer,
                                 self._response_deserializer, self._loop)
-        self._ongoing_calls.trace_call(call)
+
         return call
 
 
@@ -319,7 +285,6 @@ class Channel:
     _loop: asyncio.AbstractEventLoop
     _channel: cygrpc.AioChannel
     _unary_unary_interceptors: Optional[Sequence[UnaryUnaryClientInterceptor]]
-    _ongoing_calls: _OngoingCalls
 
     def __init__(self, target: str, options: ChannelArgumentType,
                  credentials: Optional[grpc.ChannelCredentials],
@@ -359,7 +324,6 @@ class Channel:
             _common.encode(target),
             _augment_channel_arguments(options, compression), credentials,
             self._loop)
-        self._ongoing_calls = _OngoingCalls()
 
     async def __aenter__(self):
         """Starts an asynchronous context manager.
@@ -383,22 +347,48 @@ class Channel:
         # No new calls will be accepted by the Cython channel.
         self._channel.closing()
 
-        if grace:
-            # pylint: disable=unused-variable
-            _, pending = await asyncio.wait(self._ongoing_calls.calls,
-                                            timeout=grace,
-                                            loop=self._loop)
-
-            if not pending:
-                return
-
-        # A new set is created acting as a shallow copy because
-        # when cancellation happens the calls are automatically
-        # removed from the originally set.
-        calls = WeakSet(data=self._ongoing_calls.calls)
+        # Iterate through running tasks
+        tasks = _all_tasks()
+        calls = []
+        call_tasks = []
+        for task in tasks:
+            stack = task.get_stack(limit=1)
+
+            # If the Task is created by a C-extension, the stack will be empty.
+            if not stack:
+                continue
+
+            # Locate ones created by `aio.Call`.
+            frame = stack[0]
+            candidate = frame.f_locals.get('self')
+            if candidate:
+                if isinstance(candidate, _base_call.Call):
+                    if hasattr(candidate, '_channel'):
+                        # For intercepted Call object
+                        if candidate._channel is not self._channel:
+                            continue
+                    elif hasattr(candidate, '_cython_call'):
+                        # For normal Call object
+                        if candidate._cython_call._channel is not self._channel:
+                            continue
+                    else:
+                        # Unidentified Call object
+                        raise cygrpc.InternalError(
+                            f'Unrecognized call object: {candidate}')
+
+                    calls.append(candidate)
+                    call_tasks.append(task)
+
+        # If needed, try to wait for them to finish.
+        # Call objects are not always awaitables.
+        if grace and call_tasks:
+            await asyncio.wait(call_tasks, timeout=grace, loop=self._loop)
+
+        # Time to cancel existing calls.
         for call in calls:
             call.cancel()
 
+        # Destroy the channel
         self._channel.close()
 
     async def close(self, grace: Optional[float] = None):
@@ -487,8 +477,7 @@ class Channel:
         Returns:
           A UnaryUnaryMultiCallable value for the named unary-unary method.
         """
-        return UnaryUnaryMultiCallable(self._channel, self._ongoing_calls,
-                                       _common.encode(method),
+        return UnaryUnaryMultiCallable(self._channel, _common.encode(method),
                                        request_serializer,
                                        response_deserializer,
                                        self._unary_unary_interceptors,
@@ -500,8 +489,7 @@ class Channel:
             request_serializer: Optional[SerializingFunction] = None,
             response_deserializer: Optional[DeserializingFunction] = None
     ) -> UnaryStreamMultiCallable:
-        return UnaryStreamMultiCallable(self._channel, self._ongoing_calls,
-                                        _common.encode(method),
+        return UnaryStreamMultiCallable(self._channel, _common.encode(method),
                                         request_serializer,
                                         response_deserializer, None, self._loop)
 
@@ -511,8 +499,7 @@ class Channel:
             request_serializer: Optional[SerializingFunction] = None,
             response_deserializer: Optional[DeserializingFunction] = None
     ) -> StreamUnaryMultiCallable:
-        return StreamUnaryMultiCallable(self._channel, self._ongoing_calls,
-                                        _common.encode(method),
+        return StreamUnaryMultiCallable(self._channel, _common.encode(method),
                                         request_serializer,
                                         response_deserializer, None, self._loop)
 
@@ -522,8 +509,7 @@ class Channel:
             request_serializer: Optional[SerializingFunction] = None,
             response_deserializer: Optional[DeserializingFunction] = None
     ) -> StreamStreamMultiCallable:
-        return StreamStreamMultiCallable(self._channel, self._ongoing_calls,
-                                         _common.encode(method),
+        return StreamStreamMultiCallable(self._channel, _common.encode(method),
                                          request_serializer,
                                          response_deserializer, None,
                                          self._loop)
diff --git a/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py b/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py
index 4f995bb30b9..5b06eb2bfe8 100644
--- a/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py
+++ b/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py
@@ -250,7 +250,6 @@ class MetadataCodeDetailsTest(unittest.TestCase):
             test_common.metadata_transmitted(_SERVER_TRAILING_METADATA,
                                              call.trailing_metadata()))
         self.assertIs(grpc.StatusCode.OK, call.code())
-        self.assertEqual(_DETAILS, call.details())
 
     def testSuccessfulUnaryStream(self):
         self._servicer.set_details(_DETAILS)
@@ -271,7 +270,6 @@ class MetadataCodeDetailsTest(unittest.TestCase):
                 _SERVER_TRAILING_METADATA,
                 response_iterator_call.trailing_metadata()))
         self.assertIs(grpc.StatusCode.OK, response_iterator_call.code())
-        self.assertEqual(_DETAILS, response_iterator_call.details())
 
     def testSuccessfulStreamUnary(self):
         self._servicer.set_details(_DETAILS)
@@ -290,7 +288,6 @@ class MetadataCodeDetailsTest(unittest.TestCase):
             test_common.metadata_transmitted(_SERVER_TRAILING_METADATA,
                                              call.trailing_metadata()))
         self.assertIs(grpc.StatusCode.OK, call.code())
-        self.assertEqual(_DETAILS, call.details())
 
     def testSuccessfulStreamStream(self):
         self._servicer.set_details(_DETAILS)
@@ -312,7 +309,6 @@ class MetadataCodeDetailsTest(unittest.TestCase):
                 _SERVER_TRAILING_METADATA,
                 response_iterator_call.trailing_metadata()))
         self.assertIs(grpc.StatusCode.OK, response_iterator_call.code())
-        self.assertEqual(_DETAILS, response_iterator_call.details())
 
     def testAbortedUnaryUnary(self):
         test_cases = zip(_ABORT_CODES, _EXPECTED_CLIENT_CODES,
diff --git a/src/python/grpcio_tests/tests_aio/tests.json b/src/python/grpcio_tests/tests_aio/tests.json
index d3765c7a531..e05d64ac474 100644
--- a/src/python/grpcio_tests/tests_aio/tests.json
+++ b/src/python/grpcio_tests/tests_aio/tests.json
@@ -12,7 +12,6 @@
   "unit.channel_ready_test.TestChannelReady",
   "unit.channel_test.TestChannel",
   "unit.close_channel_test.TestCloseChannel",
-  "unit.close_channel_test.TestOngoingCalls",
   "unit.compression_test.TestCompression",
   "unit.connectivity_test.TestConnectivityState",
   "unit.done_callback_test.TestDoneCallback",
diff --git a/src/python/grpcio_tests/tests_aio/unit/close_channel_test.py b/src/python/grpcio_tests/tests_aio/unit/close_channel_test.py
index f7d9de5daf5..f05c74392d9 100644
--- a/src/python/grpcio_tests/tests_aio/unit/close_channel_test.py
+++ b/src/python/grpcio_tests/tests_aio/unit/close_channel_test.py
@@ -16,12 +16,10 @@
 import asyncio
 import logging
 import unittest
-from weakref import WeakSet
 
 import grpc
 from grpc.experimental import aio
 from grpc.experimental.aio import _base_call
-from grpc.experimental.aio._channel import _OngoingCalls
 
 from src.proto.grpc.testing import messages_pb2, test_pb2_grpc
 from tests_aio.unit._test_base import AioTestBase
@@ -31,47 +29,6 @@ _UNARY_CALL_METHOD_WITH_SLEEP = '/grpc.testing.TestService/UnaryCallWithSleep'
 _LONG_TIMEOUT_THAT_SHOULD_NOT_EXPIRE = 60
 
 
-class TestOngoingCalls(unittest.TestCase):
-
-    class FakeCall(_base_call.RpcContext):
-
-        def add_done_callback(self, callback):
-            self.callback = callback
-
-        def cancel(self):
-            raise NotImplementedError
-
-        def cancelled(self):
-            raise NotImplementedError
-
-        def done(self):
-            raise NotImplementedError
-
-        def time_remaining(self):
-            raise NotImplementedError
-
-    def test_trace_call(self):
-        ongoing_calls = _OngoingCalls()
-        self.assertEqual(ongoing_calls.size(), 0)
-
-        call = TestOngoingCalls.FakeCall()
-        ongoing_calls.trace_call(call)
-        self.assertEqual(ongoing_calls.size(), 1)
-        self.assertEqual(ongoing_calls.calls, WeakSet([call]))
-
-        call.callback(call)
-        self.assertEqual(ongoing_calls.size(), 0)
-        self.assertEqual(ongoing_calls.calls, WeakSet())
-
-    def test_deleted_call(self):
-        ongoing_calls = _OngoingCalls()
-
-        call = TestOngoingCalls.FakeCall()
-        ongoing_calls.trace_call(call)
-        del (call)
-        self.assertEqual(ongoing_calls.size(), 0)
-
-
 class TestCloseChannel(AioTestBase):
 
     async def setUp(self):
@@ -114,15 +71,11 @@ class TestCloseChannel(AioTestBase):
 
         calls = [stub.UnaryCall(messages_pb2.SimpleRequest()) for _ in range(2)]
 
-        self.assertEqual(channel._ongoing_calls.size(), 2)
-
         await channel.close()
 
         for call in calls:
             self.assertTrue(call.cancelled())
 
-        self.assertEqual(channel._ongoing_calls.size(), 0)
-
     async def test_close_unary_stream(self):
         channel = aio.insecure_channel(self._server_target)
         stub = test_pb2_grpc.TestServiceStub(channel)
@@ -130,15 +83,11 @@ class TestCloseChannel(AioTestBase):
         request = messages_pb2.StreamingOutputCallRequest()
         calls = [stub.StreamingOutputCall(request) for _ in range(2)]
 
-        self.assertEqual(channel._ongoing_calls.size(), 2)
-
         await channel.close()
 
         for call in calls:
             self.assertTrue(call.cancelled())
 
-        self.assertEqual(channel._ongoing_calls.size(), 0)
-
     async def test_close_stream_unary(self):
         channel = aio.insecure_channel(self._server_target)
         stub = test_pb2_grpc.TestServiceStub(channel)
@@ -150,35 +99,38 @@ class TestCloseChannel(AioTestBase):
         for call in calls:
             self.assertTrue(call.cancelled())
 
-        self.assertEqual(channel._ongoing_calls.size(), 0)
-
     async def test_close_stream_stream(self):
         channel = aio.insecure_channel(self._server_target)
         stub = test_pb2_grpc.TestServiceStub(channel)
 
         calls = [stub.FullDuplexCall() for _ in range(2)]
 
-        self.assertEqual(channel._ongoing_calls.size(), 2)
-
         await channel.close()
 
         for call in calls:
             self.assertTrue(call.cancelled())
 
-        self.assertEqual(channel._ongoing_calls.size(), 0)
-
     async def test_close_async_context(self):
         async with aio.insecure_channel(self._server_target) as channel:
             stub = test_pb2_grpc.TestServiceStub(channel)
             calls = [
                 stub.UnaryCall(messages_pb2.SimpleRequest()) for _ in range(2)
             ]
-            self.assertEqual(channel._ongoing_calls.size(), 2)
 
         for call in calls:
             self.assertTrue(call.cancelled())
 
-        self.assertEqual(channel._ongoing_calls.size(), 0)
+    async def test_channel_isolation(self):
+        async with aio.insecure_channel(self._server_target) as channel1:
+            async with aio.insecure_channel(self._server_target) as channel2:
+                stub1 = test_pb2_grpc.TestServiceStub(channel1)
+                stub2 = test_pb2_grpc.TestServiceStub(channel2)
+
+                call1 = stub1.UnaryCall(messages_pb2.SimpleRequest())
+                call2 = stub2.UnaryCall(messages_pb2.SimpleRequest())
+
+            self.assertFalse(call1.cancelled())
+            self.assertTrue(call2.cancelled())
 
 
 if __name__ == '__main__':
diff --git a/src/upb/gen_build_yaml.py b/src/upb/gen_build_yaml.py
index f7b82993986..cb37814d0c7 100755
--- a/src/upb/gen_build_yaml.py
+++ b/src/upb/gen_build_yaml.py
@@ -26,12 +26,9 @@ out = {}
 
 try:
     out['libs'] = [{
-        'name':
-            'upb',
-        'build':
-            'all',
-        'language':
-            'c',
+        'name': 'upb',
+        'build': 'all',
+        'language': 'c',
         'src': [
             "third_party/upb/upb/decode.c",
             "third_party/upb/upb/encode.c",
@@ -50,6 +47,7 @@ try:
             "third_party/upb/upb/table.int.h",
             "third_party/upb/upb/upb.h",
         ],
+        'secure': False,
     }]
 except:
     pass
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 1532ba7258b..7fae035c1e4 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -1493,6 +1493,7 @@
       "language": "c",
       "src": sorted(used_abseil_srcs),
       "hdr": sorted(used_abseil_hdrs),
+      "secure": False,
     })
   %>
   ${makelib(grpc_abseil_lib)}
@@ -1584,7 +1585,7 @@
   $(CARES_DEP) \
   $(ADDRESS_SORTING_DEP) \
   $(UPB_DEP) \
-  $(LIBGRPC_ABSEIL_DEP) \
+  $(GRPC_ABSEIL_DEP) \
   % endif
   % endif
   % if lib.language == 'c++':
diff --git a/templates/tools/doxygen/Doxyfile.include b/templates/tools/doxygen/Doxyfile.include
index e26ae2b948a..56e6c0b0552 100644
--- a/templates/tools/doxygen/Doxyfile.include
+++ b/templates/tools/doxygen/Doxyfile.include
@@ -787,7 +787,7 @@ WARN_LOGFILE           =
 # Note: If this tag is empty the current directory is searched.
 
 INPUT                  = ${
-    ' \\\n'.join(sorted(
+    ' \\\n'.join(sorted(set(
         itertools.chain(
             itertools.chain.from_iterable(
     			      target.public_headers +
@@ -798,7 +798,7 @@ INPUT                  = ${
             glob.glob('doc/*.md'),
             glob.glob('doc/%s/*.md' % docpackage),
             [] if not internal else srcdoc)
-    ))
+    )))
 }
 
 # This tag can be used to specify the character encoding of the source files
diff --git a/templates/tools/doxygen/Doxyfile.objc.include b/templates/tools/doxygen/Doxyfile.objc.include
index 5e5867f0417..fb87d23ce1e 100644
--- a/templates/tools/doxygen/Doxyfile.objc.include
+++ b/templates/tools/doxygen/Doxyfile.objc.include
@@ -784,13 +784,13 @@ WARN_LOGFILE           =
 # Note: If this tag is empty the current directory is searched.
 
 INPUT                  = ${
-    ' \\\n'.join(sorted(
+    ' \\\n'.join(sorted(set(
         itertools.chain(
             glob.glob('src/objective-c/GRPCClient/*.h') if not internal else glob_recursive('src/objective-c/GRPCClient', '*.h'),
             glob.glob('src/objective-c/ProtoRPC/*.h'),
             glob.glob('src/objective-c/RxLibrary/*.h') if not internal else glob_recursive('src/objective-c/RxLibrary', '*.h'),
             glob.glob('doc/*.md'),
-            srcdoc)))
+            srcdoc))))
 }
 
 # This tag can be used to specify the character encoding of the source files
diff --git a/test/core/iomgr/BUILD b/test/core/iomgr/BUILD
index fb4f7c336c0..46a6c285d3a 100644
--- a/test/core/iomgr/BUILD
+++ b/test/core/iomgr/BUILD
@@ -142,7 +142,10 @@ grpc_cc_test(
         "gtest",
     ],
     language = "C++",
-    tags = ["no_windows"],  # LARGE_MACHINE is not configured for windows RBE
+    tags = [
+        "no_windows",  # LARGE_MACHINE is not configured for windows RBE
+        "notap",  # TODO(yashykt@): TSAN on TAP runs very slow. Fix it for TAP.
+    ],
     deps = [
         "//:gpr",
         "//:grpc",
diff --git a/test/core/iomgr/resolve_address_posix_test.cc b/test/core/iomgr/resolve_address_posix_test.cc
index 4247bfa5950..cf7c4f60ddc 100644
--- a/test/core/iomgr/resolve_address_posix_test.cc
+++ b/test/core/iomgr/resolve_address_posix_test.cc
@@ -231,9 +231,10 @@ int main(int argc, char** argv) {
     gpr_log(GPR_INFO, "Warning: overriding resolver setting of %s",
             resolver.get());
   }
-  if (gpr_stricmp(resolver_type, "native") == 0) {
+  if (resolver_type != nullptr && gpr_stricmp(resolver_type, "native") == 0) {
     GPR_GLOBAL_CONFIG_SET(grpc_dns_resolver, "native");
-  } else if (gpr_stricmp(resolver_type, "ares") == 0) {
+  } else if (resolver_type != nullptr &&
+             gpr_stricmp(resolver_type, "ares") == 0) {
     GPR_GLOBAL_CONFIG_SET(grpc_dns_resolver, "ares");
   } else {
     gpr_log(GPR_ERROR, "--resolver_type was not set to ares or native");
diff --git a/test/core/iomgr/resolve_address_test.cc b/test/core/iomgr/resolve_address_test.cc
index 48d3f8eb105..ca7c914f51b 100644
--- a/test/core/iomgr/resolve_address_test.cc
+++ b/test/core/iomgr/resolve_address_test.cc
@@ -353,9 +353,10 @@ int main(int argc, char** argv) {
     gpr_log(GPR_INFO, "Warning: overriding resolver setting of %s",
             resolver.get());
   }
-  if (gpr_stricmp(resolver_type, "native") == 0) {
+  if (resolver_type != nullptr && gpr_stricmp(resolver_type, "native") == 0) {
     GPR_GLOBAL_CONFIG_SET(grpc_dns_resolver, "native");
-  } else if (gpr_stricmp(resolver_type, "ares") == 0) {
+  } else if (resolver_type != nullptr &&
+             gpr_stricmp(resolver_type, "ares") == 0) {
 #ifndef GRPC_UV
     GPR_GLOBAL_CONFIG_SET(grpc_dns_resolver, "ares");
 #endif
diff --git a/test/core/security/credentials_test.cc b/test/core/security/credentials_test.cc
index 85c70bcaf19..b58973d4c34 100644
--- a/test/core/security/credentials_test.cc
+++ b/test/core/security/credentials_test.cc
@@ -982,6 +982,41 @@ static void test_sts_creds_success(void) {
   gpr_free(actor_token_path);
 }
 
+static void test_sts_creds_token_file_not_found(void) {
+  grpc_core::ExecCtx exec_ctx;
+  grpc_auth_metadata_context auth_md_ctx = {test_service_url, test_method,
+                                            nullptr, nullptr};
+  grpc_sts_credentials_options valid_options = {
+      test_sts_endpoint_url,           // sts_endpoint_url
+      "resource",                      // resource
+      "audience",                      // audience
+      "scope",                         // scope
+      "requested_token_type",          // requested_token_type
+      "/some/completely/random/path",  // subject_token_path
+      test_signed_jwt_token_type,      // subject_token_type
+      "",                              // actor_token_path
+      ""                               // actor_token_type
+  };
+  grpc_call_credentials* creds =
+      grpc_sts_credentials_create(&valid_options, nullptr);
+
+  /* Check security level. */
+  GPR_ASSERT(creds->min_security_level() == GRPC_PRIVACY_AND_INTEGRITY);
+
+  request_metadata_state* state = make_request_metadata_state(
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+          "Error occurred when fetching oauth2 token."),
+      nullptr, 0);
+  grpc_httpcli_set_override(httpcli_get_should_not_be_called,
+                            httpcli_post_should_not_be_called);
+  run_request_metadata_test(creds, auth_md_ctx, state);
+  grpc_core::ExecCtx::Get()->Flush();
+
+  /* Cleanup. */
+  creds->Unref();
+  grpc_httpcli_set_override(nullptr, nullptr);
+}
+
 static void test_sts_creds_no_actor_token_success(void) {
   grpc_core::ExecCtx exec_ctx;
   expected_md emd[] = {
@@ -1687,6 +1722,7 @@ int main(int argc, char** argv) {
   test_sts_creds_no_actor_token_success();
   test_sts_creds_load_token_failure();
   test_sts_creds_http_failure();
+  test_sts_creds_token_file_not_found();
   test_jwt_creds_lifetime();
   test_jwt_creds_success();
   test_jwt_creds_signing_failure();
diff --git a/test/core/security/oauth2_utils.cc b/test/core/security/oauth2_utils.cc
index cab06f90ff1..0885a1ac876 100644
--- a/test/core/security/oauth2_utils.cc
+++ b/test/core/security/oauth2_utils.cc
@@ -27,6 +27,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/security/credentials/credentials.h"
 
 typedef struct {
@@ -63,17 +64,14 @@ static void on_oauth2_response(void* arg, grpc_error* error) {
   gpr_mu_unlock(request->mu);
 }
 
-static void destroy_after_shutdown(void* pollset, grpc_error* /*error*/) {
-  grpc_pollset_destroy(reinterpret_cast<grpc_pollset*>(pollset));
-  gpr_free(pollset);
-}
+static void do_nothing(void* /*arg*/, grpc_error* /*error*/) {}
 
 char* grpc_test_fetch_oauth2_token_with_credentials(
     grpc_call_credentials* creds) {
   oauth2_request request;
-  request = {};
+  memset(&request, 0, sizeof(request));
   grpc_core::ExecCtx exec_ctx;
-  grpc_closure destroy_after_shutdown_closure;
+  grpc_closure do_nothing_closure;
   grpc_auth_metadata_context null_ctx = {"", "", nullptr, nullptr};
 
   grpc_pollset* pollset =
@@ -82,8 +80,8 @@ char* grpc_test_fetch_oauth2_token_with_credentials(
   request.pops = grpc_polling_entity_create_from_pollset(pollset);
   request.is_done = false;
 
-  GRPC_CLOSURE_INIT(&destroy_after_shutdown_closure, destroy_after_shutdown,
-                    pollset, grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&do_nothing_closure, do_nothing, nullptr,
+                    grpc_schedule_on_exec_ctx);
 
   GRPC_CLOSURE_INIT(&request.closure, on_oauth2_response, &request,
                     grpc_schedule_on_exec_ctx);
@@ -110,6 +108,9 @@ char* grpc_test_fetch_oauth2_token_with_credentials(
   gpr_mu_unlock(request.mu);
 
   grpc_pollset_shutdown(grpc_polling_entity_pollset(&request.pops),
-                        &destroy_after_shutdown_closure);
+                        &do_nothing_closure);
+  grpc_core::ExecCtx::Get()->Flush();
+  grpc_pollset_destroy(grpc_polling_entity_pollset(&request.pops));
+  gpr_free(pollset);
   return request.token;
 }
diff --git a/test/cpp/interop/BUILD b/test/cpp/interop/BUILD
index 433d354e9b6..c54cc4719e0 100644
--- a/test/cpp/interop/BUILD
+++ b/test/cpp/interop/BUILD
@@ -227,3 +227,20 @@ grpc_cc_binary(
         "//test/cpp/util:test_config",
     ],
 )
+
+grpc_cc_binary(
+    name = "http2_client",
+    srcs = [
+        "http2_client.cc",
+        "http2_client.h",
+    ],
+    deps = [
+        "//:grpc++",
+        "//src/proto/grpc/testing:empty_proto",
+        "//src/proto/grpc/testing:messages_proto",
+        "//src/proto/grpc/testing:test_proto",
+        "//test/core/util:grpc_test_util",
+        "//test/cpp/util:test_config",
+        "//test/cpp/util:test_util",
+    ],
+)
diff --git a/test/cpp/interop/xds_interop_client.cc b/test/cpp/interop/xds_interop_client.cc
index 3b80ea4eab3..7d6233de5e8 100644
--- a/test/cpp/interop/xds_interop_client.cc
+++ b/test/cpp/interop/xds_interop_client.cc
@@ -227,6 +227,7 @@ int main(int argc, char** argv) {
 
   std::vector<std::thread> test_threads;
 
+  test_threads.reserve(FLAGS_num_channels);
   for (int i = 0; i < FLAGS_num_channels; i++) {
     test_threads.emplace_back(
         std::thread(&RunTestLoop, FLAGS_server, duration_per_query));
diff --git a/test/cpp/microbenchmarks/BUILD b/test/cpp/microbenchmarks/BUILD
index db7c9db05ae..df2cedfeed3 100644
--- a/test/cpp/microbenchmarks/BUILD
+++ b/test/cpp/microbenchmarks/BUILD
@@ -14,7 +14,7 @@
 
 licenses(["notice"])  # Apache v2
 
-load("//bazel:grpc_build_system.bzl", "grpc_cc_binary", "grpc_cc_library", "grpc_cc_test", "grpc_package")
+load("//bazel:grpc_build_system.bzl", "grpc_cc_library", "grpc_cc_test", "grpc_package")
 
 grpc_package(name = "test/cpp/microbenchmarks")
 
@@ -39,7 +39,6 @@ grpc_cc_library(
     external_deps = [
         "benchmark",
     ],
-    tags = ["no_windows"],
     deps = [
         "//:grpc++_unsecure",
         "//src/proto/grpc/testing:echo_proto",
@@ -48,75 +47,121 @@ grpc_cc_library(
     ],
 )
 
-grpc_cc_binary(
-    name = "bm_closure",
+# Need a secure version of helpers to benchmark opencensus
+grpc_cc_library(
+    name = "helpers_secure",
     testonly = 1,
+    srcs = ["helpers.cc"],
+    hdrs = [
+        "fullstack_context_mutators.h",
+        "fullstack_fixtures.h",
+        "helpers.h",
+    ],
+    external_deps = [
+        "benchmark",
+    ],
+    deps = [
+        "//:grpc++",
+        "//src/proto/grpc/testing:echo_proto",
+        "//test/core/util:grpc_test_util",
+        "//test/cpp/util:test_config",
+    ],
+)
+
+grpc_cc_test(
+    name = "bm_closure",
     srcs = ["bm_closure.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_alarm",
-    testonly = 1,
     srcs = ["bm_alarm.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_arena",
-    testonly = 1,
     srcs = ["bm_arena.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+        "notsan",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_byte_buffer",
-    testonly = 1,
     srcs = ["bm_byte_buffer.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_channel",
-    testonly = 1,
     srcs = ["bm_channel.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_call_create",
-    testonly = 1,
     srcs = ["bm_call_create.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_cq",
-    testonly = 1,
     srcs = ["bm_cq.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_cq_multiple_threads",
-    testonly = 1,
     srcs = ["bm_cq_multiple_threads.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_error",
-    testonly = 1,
     srcs = ["bm_error.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
@@ -126,13 +171,16 @@ grpc_cc_library(
     hdrs = [
         "fullstack_streaming_ping_pong.h",
     ],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_fullstack_streaming_ping_pong",
-    testonly = 1,
+    size = "large",
     srcs = [
         "bm_fullstack_streaming_ping_pong.cc",
     ],
@@ -152,9 +200,8 @@ grpc_cc_library(
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_fullstack_streaming_pump",
-    testonly = 1,
     srcs = [
         "bm_fullstack_streaming_pump.cc",
     ],
@@ -165,14 +212,11 @@ grpc_cc_binary(
     deps = [":fullstack_streaming_pump_h"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_fullstack_trickle",
-    testonly = 1,
+    size = "large",
     srcs = ["bm_fullstack_trickle.cc"],
-    tags = [
-        "no_mac",  # to emulate "excluded_poll_engines: poll"
-        "no_windows",
-    ],
+    tags = ["manual"],
     deps = [":helpers"],
 )
 
@@ -185,9 +229,8 @@ grpc_cc_library(
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_fullstack_unary_ping_pong",
-    testonly = 1,
     srcs = [
         "bm_fullstack_unary_ping_pong.cc",
     ],
@@ -198,47 +241,56 @@ grpc_cc_binary(
     deps = [":fullstack_unary_ping_pong_h"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_metadata",
-    testonly = 1,
     srcs = ["bm_metadata.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_chttp2_hpack",
-    testonly = 1,
     srcs = ["bm_chttp2_hpack.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_opencensus_plugin",
-    testonly = 1,
     srcs = ["bm_opencensus_plugin.cc"],
     language = "C++",
     deps = [
-        ":helpers",
+        ":helpers_secure",
         "//:grpc_opencensus_plugin",
         "//src/proto/grpc/testing:echo_proto",
     ],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_timer",
-    testonly = 1,
     srcs = ["bm_timer.cc"],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_threadpool",
-    testonly = 1,
+    size = "large",
     srcs = ["bm_threadpool.cc"],
-    tags = ["no_windows"],
+    tags = ["manual"],
+    uses_polling = False,
     deps = [":helpers"],
 )
 
@@ -253,7 +305,7 @@ grpc_cc_library(
     deps = [
         ":helpers",
         "//src/proto/grpc/testing:echo_proto",
-        "//test/cpp/util:test_util",
+        "//test/cpp/util:test_util_unsecure",
     ],
 )
 
@@ -269,13 +321,15 @@ grpc_cc_library(
     ],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_callback_unary_ping_pong",
-    testonly = 1,
     srcs = [
         "bm_callback_unary_ping_pong.cc",
     ],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",
+        "no_windows",
+    ],
     deps = [":callback_unary_ping_pong_h"],
 )
 
@@ -291,12 +345,15 @@ grpc_cc_library(
     ],
 )
 
-grpc_cc_binary(
+grpc_cc_test(
     name = "bm_callback_streaming_ping_pong",
-    testonly = 1,
+    size = "large",
     srcs = [
         "bm_callback_streaming_ping_pong.cc",
     ],
-    tags = ["no_windows"],
+    tags = [
+        "no_mac",  # to emulate "excluded_poll_engines: poll"
+        "no_windows",
+    ],
     deps = [":callback_streaming_ping_pong_h"],
 )
diff --git a/test/cpp/microbenchmarks/bm_call_create.cc b/test/cpp/microbenchmarks/bm_call_create.cc
index f09f9e4baa3..803ad38f1c5 100644
--- a/test/cpp/microbenchmarks/bm_call_create.cc
+++ b/test/cpp/microbenchmarks/bm_call_create.cc
@@ -513,7 +513,8 @@ static void BM_IsolatedFilter(benchmark::State& state) {
       static_cast<grpc_channel_stack*>(gpr_zalloc(channel_size));
   GPR_ASSERT(GRPC_LOG_IF_ERROR(
       "channel_stack_init",
-      grpc_channel_stack_init(1, FilterDestroy, channel_stack, &filters[0],
+      grpc_channel_stack_init(1, FilterDestroy, channel_stack,
+                              filters.size() == 0 ? nullptr : &filters[0],
                               filters.size(), &channel_args,
                               fixture.flags & REQUIRES_TRANSPORT
                                   ? &dummy_transport::dummy_transport
diff --git a/test/cpp/microbenchmarks/bm_opencensus_plugin.cc b/test/cpp/microbenchmarks/bm_opencensus_plugin.cc
index 4f4884bef9b..908d34aa19f 100644
--- a/test/cpp/microbenchmarks/bm_opencensus_plugin.cc
+++ b/test/cpp/microbenchmarks/bm_opencensus_plugin.cc
@@ -22,7 +22,8 @@
 
 #include "absl/base/call_once.h"
 #include "absl/strings/str_cat.h"
-#include "include/grpc++/grpc++.h"
+#include "include/grpc/grpc.h"
+#include "include/grpcpp/grpcpp.h"
 #include "include/grpcpp/opencensus.h"
 #include "opencensus/stats/stats.h"
 #include "src/cpp/ext/filters/census/grpc_plugin.h"
@@ -100,6 +101,13 @@ static void BM_E2eLatencyCensusDisabled(benchmark::State& state) {
 BENCHMARK(BM_E2eLatencyCensusDisabled);
 
 static void BM_E2eLatencyCensusEnabled(benchmark::State& state) {
+  // Avoid a data race between registering plugin and shutdown of previous
+  // test (order-dependent) by doing an init/shutdown so that any previous
+  // shutdowns are fully complete first.
+  grpc_init();
+  grpc_shutdown_blocking();
+
+  // Now start the test by registering the plugin (once in the execution)
   RegisterOnce();
   // This we can safely repeat, and doing so clears accumulated data to avoid
   // initialization costs varying between runs.
diff --git a/test/cpp/microbenchmarks/bm_timer.cc b/test/cpp/microbenchmarks/bm_timer.cc
index 7a493df5826..db6ab0a073e 100644
--- a/test/cpp/microbenchmarks/bm_timer.cc
+++ b/test/cpp/microbenchmarks/bm_timer.cc
@@ -81,7 +81,7 @@ static void BM_TimerBatch(benchmark::State& state) {
       grpc_timer_init(&timer_closure->timer, deadline, &timer_closure->closure);
     }
     if (check) {
-      grpc_millis next;
+      grpc_millis next = GRPC_MILLIS_INF_FUTURE;
       grpc_timer_check(&next);
     }
     for (grpc_millis deadline = start; deadline != end; deadline += increment) {
diff --git a/tools/bazel b/tools/bazel
index d5d517ba99e..a1785078e73 100755
--- a/tools/bazel
+++ b/tools/bazel
@@ -33,8 +33,7 @@ then
 fi
 
 VERSION=1.0.0
-
-echo "INFO: Running bazel wrapper (see //tools/bazel for details), bazel version $VERSION will be used instead of system-wide bazel installation."
+echo "INFO: Running bazel wrapper (see //tools/bazel for details), bazel version $VERSION will be used instead of system-wide bazel installation." >&2
 
 BASEURL=https://github.com/bazelbuild/bazel/releases/download/
 pushd "$(dirname "$0")" >/dev/null
@@ -48,7 +47,7 @@ case $(uname -sm) in
     suffix=darwin-x86_64
     ;;
   *)
-    echo "Unsupported architecture: $(uname -sm)"
+    echo "Unsupported architecture: $(uname -sm)" >&2
     exit 1
     ;;
 esac
diff --git a/tools/distrib/python/grpcio_tools/README.rst b/tools/distrib/python/grpcio_tools/README.rst
index 2fe79350a84..15a76416fb1 100644
--- a/tools/distrib/python/grpcio_tools/README.rst
+++ b/tools/distrib/python/grpcio_tools/README.rst
@@ -61,7 +61,7 @@ GCC-like stuff, but you may end up having a bad time.
 ::
 
   $ export REPO_ROOT=grpc  # REPO_ROOT can be any directory of your choice
-  $ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc $REPO_ROOT
+  $ git clone -b RELEASE_TAG_HERE https://github.com/grpc/grpc $REPO_ROOT
   $ cd $REPO_ROOT
   $ git submodule update --init
 
diff --git a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_4/Dockerfile b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_4/Dockerfile
index 55b1b1e731d..a645b1802af 100644
--- a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_4/Dockerfile
+++ b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_4/Dockerfile
@@ -27,11 +27,11 @@ RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A170311380
 RUN \curl -sSL https://get.rvm.io | bash -s stable
 
 # Install Ruby 2.4
-RUN /bin/bash -l -c "rvm install ruby-2.4.5"
-RUN /bin/bash -l -c "rvm use --default ruby-2.4.5"
+RUN /bin/bash -l -c "rvm install ruby-2.4.9"
+RUN /bin/bash -l -c "rvm use --default ruby-2.4.9"
 RUN /bin/bash -l -c "echo 'gem: --no-document' > ~/.gemrc"
 RUN /bin/bash -l -c "echo 'export PATH=/usr/local/rvm/bin:$PATH' >> ~/.bashrc"
-RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.4.5' >> ~/.bashrc"
+RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.4.9' >> ~/.bashrc"
 RUN /bin/bash -l -c "gem install bundler -v 1.17.3 --no-document"
 
 RUN mkdir /var/local/jenkins
diff --git a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_5/Dockerfile b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_5/Dockerfile
index bed4b3a93ef..44b36e55277 100644
--- a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_5/Dockerfile
+++ b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_5/Dockerfile
@@ -27,11 +27,11 @@ RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A170311380
 RUN \curl -sSL https://get.rvm.io | bash -s stable
 
 # Install Ruby 2.5
-RUN /bin/bash -l -c "rvm install ruby-2.5.3"
-RUN /bin/bash -l -c "rvm use --default ruby-2.5.3"
+RUN /bin/bash -l -c "rvm install ruby-2.5.7"
+RUN /bin/bash -l -c "rvm use --default ruby-2.5.7"
 RUN /bin/bash -l -c "echo 'gem: --no-document' > ~/.gemrc"
 RUN /bin/bash -l -c "echo 'export PATH=/usr/local/rvm/bin:$PATH' >> ~/.bashrc"
-RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.5.3' >> ~/.bashrc"
+RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.5.7' >> ~/.bashrc"
 RUN /bin/bash -l -c "gem install bundler -v 1.17.3 --no-document"
 
 RUN mkdir /var/local/jenkins
diff --git a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_6/Dockerfile b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_6/Dockerfile
index af1839eba93..fab8d53b2be 100644
--- a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_6/Dockerfile
+++ b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_6/Dockerfile
@@ -27,11 +27,11 @@ RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A170311380
 RUN \curl -sSL https://get.rvm.io | bash -s stable
 
 # Install Ruby 2.6
-RUN /bin/bash -l -c "rvm install ruby-2.6.0"
-RUN /bin/bash -l -c "rvm use --default ruby-2.6.0"
+RUN /bin/bash -l -c "rvm install ruby-2.6.5"
+RUN /bin/bash -l -c "rvm use --default ruby-2.6.5"
 RUN /bin/bash -l -c "echo 'gem: --no-document' > ~/.gemrc"
 RUN /bin/bash -l -c "echo 'export PATH=/usr/local/rvm/bin:$PATH' >> ~/.bashrc"
-RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.6.0' >> ~/.bashrc"
+RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.6.5' >> ~/.bashrc"
 RUN /bin/bash -l -c "gem install bundler --no-document"
 
 RUN mkdir /var/local/jenkins
diff --git a/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_7/Dockerfile b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_7/Dockerfile
new file mode 100644
index 00000000000..d5aeb9f22a9
--- /dev/null
+++ b/tools/dockerfile/distribtest/ruby_jessie_x64_ruby_2_7/Dockerfile
@@ -0,0 +1,40 @@
+# Copyright 2020 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM debian:jessie
+
+# Install Git and basic packages.
+RUN apt-get update && apt-get install -y \
+  curl \
+  gcc && apt-get clean
+
+#==================
+# Ruby dependencies
+
+# Install rvm
+RUN gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB
+RUN \curl -sSL https://get.rvm.io | bash -s stable
+
+# Install Ruby 2.7
+RUN /bin/bash -l -c "rvm install ruby-2.7.0"
+RUN /bin/bash -l -c "rvm use --default ruby-2.7.0"
+RUN /bin/bash -l -c "echo 'gem: --no-document' > ~/.gemrc"
+RUN /bin/bash -l -c "echo 'export PATH=/usr/local/rvm/bin:$PATH' >> ~/.bashrc"
+RUN /bin/bash -l -c "echo 'rvm --default use ruby-2.7.0' >> ~/.bashrc"
+RUN /bin/bash -l -c "gem install bundler --no-document"
+
+RUN mkdir /var/local/jenkins
+
+# Define the default command.
+CMD ["bash"]
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 46d038eac5d..d1da5829623 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -826,7 +826,6 @@ include/grpc++/impl/codegen/completion_queue_tag.h \
 include/grpc++/impl/codegen/config.h \
 include/grpc++/impl/codegen/config_protobuf.h \
 include/grpc++/impl/codegen/core_codegen.h \
-include/grpc++/impl/codegen/core_codegen.h \
 include/grpc++/impl/codegen/core_codegen_interface.h \
 include/grpc++/impl/codegen/create_auth_context.h \
 include/grpc++/impl/codegen/grpc_library.h \
@@ -975,7 +974,6 @@ include/grpcpp/impl/codegen/completion_queue_tag.h \
 include/grpcpp/impl/codegen/config.h \
 include/grpcpp/impl/codegen/config_protobuf.h \
 include/grpcpp/impl/codegen/core_codegen.h \
-include/grpcpp/impl/codegen/core_codegen.h \
 include/grpcpp/impl/codegen/core_codegen_interface.h \
 include/grpcpp/impl/codegen/create_auth_context.h \
 include/grpcpp/impl/codegen/delegating_channel.h \
diff --git a/tools/doxygen/Doxyfile.core b/tools/doxygen/Doxyfile.core
index 0c0e95a1920..9ab5b3e429c 100644
--- a/tools/doxygen/Doxyfile.core
+++ b/tools/doxygen/Doxyfile.core
@@ -816,43 +816,28 @@ include/grpc/grpc_posix.h \
 include/grpc/grpc_security.h \
 include/grpc/grpc_security_constants.h \
 include/grpc/impl/codegen/atm.h \
-include/grpc/impl/codegen/atm.h \
-include/grpc/impl/codegen/atm_gcc_atomic.h \
 include/grpc/impl/codegen/atm_gcc_atomic.h \
 include/grpc/impl/codegen/atm_gcc_sync.h \
-include/grpc/impl/codegen/atm_gcc_sync.h \
-include/grpc/impl/codegen/atm_windows.h \
 include/grpc/impl/codegen/atm_windows.h \
 include/grpc/impl/codegen/byte_buffer.h \
 include/grpc/impl/codegen/byte_buffer_reader.h \
 include/grpc/impl/codegen/compression_types.h \
 include/grpc/impl/codegen/connectivity_state.h \
 include/grpc/impl/codegen/fork.h \
-include/grpc/impl/codegen/fork.h \
-include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_types.h \
-include/grpc/impl/codegen/gpr_types.h \
 include/grpc/impl/codegen/grpc_types.h \
 include/grpc/impl/codegen/log.h \
-include/grpc/impl/codegen/log.h \
-include/grpc/impl/codegen/port_platform.h \
 include/grpc/impl/codegen/port_platform.h \
 include/grpc/impl/codegen/propagation_bits.h \
 include/grpc/impl/codegen/slice.h \
 include/grpc/impl/codegen/status.h \
 include/grpc/impl/codegen/sync.h \
-include/grpc/impl/codegen/sync.h \
 include/grpc/impl/codegen/sync_abseil.h \
-include/grpc/impl/codegen/sync_abseil.h \
-include/grpc/impl/codegen/sync_custom.h \
 include/grpc/impl/codegen/sync_custom.h \
 include/grpc/impl/codegen/sync_generic.h \
-include/grpc/impl/codegen/sync_generic.h \
-include/grpc/impl/codegen/sync_posix.h \
 include/grpc/impl/codegen/sync_posix.h \
 include/grpc/impl/codegen/sync_windows.h \
-include/grpc/impl/codegen/sync_windows.h \
 include/grpc/load_reporting.h \
 include/grpc/slice.h \
 include/grpc/slice_buffer.h \
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 8318caf4f27..04cb62c32bc 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -816,43 +816,28 @@ include/grpc/grpc_posix.h \
 include/grpc/grpc_security.h \
 include/grpc/grpc_security_constants.h \
 include/grpc/impl/codegen/atm.h \
-include/grpc/impl/codegen/atm.h \
-include/grpc/impl/codegen/atm_gcc_atomic.h \
 include/grpc/impl/codegen/atm_gcc_atomic.h \
 include/grpc/impl/codegen/atm_gcc_sync.h \
-include/grpc/impl/codegen/atm_gcc_sync.h \
-include/grpc/impl/codegen/atm_windows.h \
 include/grpc/impl/codegen/atm_windows.h \
 include/grpc/impl/codegen/byte_buffer.h \
 include/grpc/impl/codegen/byte_buffer_reader.h \
 include/grpc/impl/codegen/compression_types.h \
 include/grpc/impl/codegen/connectivity_state.h \
 include/grpc/impl/codegen/fork.h \
-include/grpc/impl/codegen/fork.h \
-include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_slice.h \
 include/grpc/impl/codegen/gpr_types.h \
-include/grpc/impl/codegen/gpr_types.h \
 include/grpc/impl/codegen/grpc_types.h \
 include/grpc/impl/codegen/log.h \
-include/grpc/impl/codegen/log.h \
-include/grpc/impl/codegen/port_platform.h \
 include/grpc/impl/codegen/port_platform.h \
 include/grpc/impl/codegen/propagation_bits.h \
 include/grpc/impl/codegen/slice.h \
 include/grpc/impl/codegen/status.h \
 include/grpc/impl/codegen/sync.h \
-include/grpc/impl/codegen/sync.h \
 include/grpc/impl/codegen/sync_abseil.h \
-include/grpc/impl/codegen/sync_abseil.h \
-include/grpc/impl/codegen/sync_custom.h \
 include/grpc/impl/codegen/sync_custom.h \
 include/grpc/impl/codegen/sync_generic.h \
-include/grpc/impl/codegen/sync_generic.h \
-include/grpc/impl/codegen/sync_posix.h \
 include/grpc/impl/codegen/sync_posix.h \
 include/grpc/impl/codegen/sync_windows.h \
-include/grpc/impl/codegen/sync_windows.h \
 include/grpc/load_reporting.h \
 include/grpc/slice.h \
 include/grpc/slice_buffer.h \
diff --git a/tools/remote_build/rbe_common.bazelrc b/tools/remote_build/rbe_common.bazelrc
index af024760cd4..5b5dcdf9d93 100644
--- a/tools/remote_build/rbe_common.bazelrc
+++ b/tools/remote_build/rbe_common.bazelrc
@@ -55,7 +55,7 @@ build:asan --copt=-gmlt
 # use double the default value for "moderate" and "long" timeout as sanitizer
 # tests tend to be slower
 build:asan --test_timeout=60,600,1800,3600
-build:asan --test_tag_filters=-no_linux,-qps_json_driver
+build:asan --test_tag_filters=-no_linux,-noasan,-qps_json_driver
 
 # memory sanitizer: most settings are already in %workspace%/.bazelrc
 # we only need a few additional ones that are Foundry specific
@@ -78,7 +78,7 @@ build:tsan --copt=-gmlt
 # use double the default value for "moderate" and "long" timeout as sanitizer
 # tests tend to be slower
 build:tsan --test_timeout=60,600,1800,3600
-build:tsan --test_tag_filters=-no_linux,-qps_json_driver
+build:tsan --test_tag_filters=-no_linux,-notsan,-qps_json_driver
 build:tsan --extra_execution_platforms=@rbe_default//config:platform
 
 # undefined behavior sanitizer: most settings are already in %workspace%/.bazelrc
diff --git a/tools/run_tests/artifacts/distribtest_targets.py b/tools/run_tests/artifacts/distribtest_targets.py
index 63c84481f7c..e50b446eac6 100644
--- a/tools/run_tests/artifacts/distribtest_targets.py
+++ b/tools/run_tests/artifacts/distribtest_targets.py
@@ -340,6 +340,7 @@ def targets():
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_4'),
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_5'),
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_6'),
+        # RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_7'),
         RubyDistribTest('linux', 'x64', 'centos6'),
         RubyDistribTest('linux', 'x64', 'centos7'),
         RubyDistribTest('linux', 'x64', 'fedora23'),
diff --git a/tools/run_tests/sanity/check_deprecated_grpc++.py b/tools/run_tests/sanity/check_deprecated_grpc++.py
index 4ec49fae394..02307fedaa8 100755
--- a/tools/run_tests/sanity/check_deprecated_grpc++.py
+++ b/tools/run_tests/sanity/check_deprecated_grpc++.py
@@ -51,10 +51,8 @@ expected_files = [
     "include/grpc++/impl/rpc_service_method.h",
     "include/grpc++/impl/method_handler_impl.h",
     "include/grpc++/impl/server_builder_plugin.h",
-    "include/grpc++/impl/sync_cxx11.h",
     "include/grpc++/impl/server_initializer.h",
     "include/grpc++/impl/serialization_traits.h",
-    "include/grpc++/impl/sync_no_cxx11.h",
     "include/grpc++/impl/codegen/sync_stream.h",
     "include/grpc++/impl/codegen/channel_interface.h",
     "include/grpc++/impl/codegen/config_protobuf.h",