diff --git a/BUILD b/BUILD
index 09880d886ba..e781c0d9f15 100644
--- a/BUILD
+++ b/BUILD
@@ -148,7 +148,7 @@ python_config_settings()
 # This should be updated along with build_handwritten.yaml
 g_stands_for = "green"  # @unused
 
-core_version = "20.0.0"  # @unused
+core_version = "21.0.0"  # @unused
 
 version = "1.43.0-dev"  # @unused
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3e38106db0a..54e91136a54 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,8 +26,8 @@ cmake_minimum_required(VERSION 3.5.1)
 
 set(PACKAGE_NAME          "grpc")
 set(PACKAGE_VERSION       "1.43.0-dev")
-set(gRPC_CORE_VERSION     "20.0.0")
-set(gRPC_CORE_SOVERSION   "20")
+set(gRPC_CORE_VERSION     "21.0.0")
+set(gRPC_CORE_SOVERSION   "21")
 set(gRPC_CPP_VERSION      "1.43.0-dev")
 set(gRPC_CPP_SOVERSION    "1.43")
 set(gRPC_CSHARP_VERSION   "2.43.0-dev")
diff --git a/Makefile b/Makefile
index 67904f12a5d..f98a7682a08 100644
--- a/Makefile
+++ b/Makefile
@@ -454,7 +454,7 @@ E = @echo
 Q = @
 endif
 
-CORE_VERSION = 20.0.0
+CORE_VERSION = 21.0.0
 CPP_VERSION = 1.43.0-dev
 CSHARP_VERSION = 2.43.0-dev
 
@@ -492,7 +492,7 @@ SHARED_EXT_CORE = dll
 SHARED_EXT_CPP = dll
 SHARED_EXT_CSHARP = dll
 SHARED_PREFIX =
-SHARED_VERSION_CORE = -20
+SHARED_VERSION_CORE = -21
 SHARED_VERSION_CPP = -1
 SHARED_VERSION_CSHARP = -2
 else ifeq ($(SYSTEM),Darwin)
@@ -891,8 +891,8 @@ $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE):
 ifeq ($(SYSTEM),Darwin)
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)address_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBADDRESS_SORTING_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libaddress_sorting.so.20 -o $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBADDRESS_SORTING_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
-	$(Q) ln -sf $(SHARED_PREFIX)address_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).so.20
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libaddress_sorting.so.21 -o $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBADDRESS_SORTING_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
+	$(Q) ln -sf $(SHARED_PREFIX)address_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).so.21
 	$(Q) ln -sf $(SHARED_PREFIX)address_sorting$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libaddress_sorting$(SHARED_VERSION_CORE).so
 endif
 endif
@@ -1022,8 +1022,8 @@ $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBGPR_OB
 ifeq ($(SYSTEM),Darwin)
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)gpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGPR_OBJS) $(LIBDIR)/$(CONFIG)/libupb.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgpr.so.20 -o $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGPR_OBJS) $(LIBDIR)/$(CONFIG)/libupb.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
-	$(Q) ln -sf $(SHARED_PREFIX)gpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).so.20
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgpr.so.21 -o $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGPR_OBJS) $(LIBDIR)/$(CONFIG)/libupb.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
+	$(Q) ln -sf $(SHARED_PREFIX)gpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).so.21
 	$(Q) ln -sf $(SHARED_PREFIX)gpr$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgpr$(SHARED_VERSION_CORE).so
 endif
 endif
@@ -1692,8 +1692,8 @@ $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBGRPC_
 ifeq ($(SYSTEM),Darwin)
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)grpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_OBJS) $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(OPENSSL_MERGE_LIBS) $(LDLIBS_SECURE) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpc.so.20 -o $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_OBJS) $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(OPENSSL_MERGE_LIBS) $(LDLIBS_SECURE) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
-	$(Q) ln -sf $(SHARED_PREFIX)grpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).so.20
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpc.so.21 -o $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_OBJS) $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(OPENSSL_MERGE_LIBS) $(LDLIBS_SECURE) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
+	$(Q) ln -sf $(SHARED_PREFIX)grpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).so.21
 	$(Q) ln -sf $(SHARED_PREFIX)grpc$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc$(SHARED_VERSION_CORE).so
 endif
 endif
@@ -1740,8 +1740,8 @@ $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE):
 ifeq ($(SYSTEM),Darwin)
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)grpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_CSHARP_EXT_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpc_csharp_ext.so.20 -o $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_CSHARP_EXT_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
-	$(Q) ln -sf $(SHARED_PREFIX)grpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).so.20
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpc_csharp_ext.so.21 -o $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_CSHARP_EXT_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
+	$(Q) ln -sf $(SHARED_PREFIX)grpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).so.21
 	$(Q) ln -sf $(SHARED_PREFIX)grpc_csharp_ext$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc_csharp_ext$(SHARED_VERSION_CORE).so
 endif
 endif
@@ -2094,8 +2094,8 @@ $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $
 ifeq ($(SYSTEM),Darwin)
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)grpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpc_unsecure.so.20 -o $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
-	$(Q) ln -sf $(SHARED_PREFIX)grpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).so.20
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libgrpc_unsecure.so.21 -o $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBGRPC_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libaddress_sorting.a $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
+	$(Q) ln -sf $(SHARED_PREFIX)grpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).so.21
 	$(Q) ln -sf $(SHARED_PREFIX)grpc_unsecure$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libgrpc_unsecure$(SHARED_VERSION_CORE).so
 endif
 endif
@@ -2490,8 +2490,8 @@ $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE): $(LIBUPB_OB
 ifeq ($(SYSTEM),Darwin)
 	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -install_name $(SHARED_PREFIX)upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) -dynamiclib -o $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBUPB_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
 else
-	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libupb.so.20 -o $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBUPB_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
-	$(Q) ln -sf $(SHARED_PREFIX)upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).so.20
+	$(Q) $(LDXX) $(LDFLAGS) -L$(LIBDIR)/$(CONFIG) -shared -Wl,-soname,libupb.so.21 -o $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBUPB_OBJS) $(ZLIB_MERGE_LIBS) $(CARES_MERGE_LIBS) $(ADDRESS_SORTING_MERGE_LIBS) $(RE2_MERGE_LIBS) $(UPB_MERGE_LIBS) $(GRPC_ABSEIL_MERGE_LIBS) $(LDLIBS)
+	$(Q) ln -sf $(SHARED_PREFIX)upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).so.21
 	$(Q) ln -sf $(SHARED_PREFIX)upb$(SHARED_VERSION_CORE).$(SHARED_EXT_CORE) $(LIBDIR)/$(CONFIG)/libupb$(SHARED_VERSION_CORE).so
 endif
 endif
diff --git a/build_config.rb b/build_config.rb
index 17abefa0c28..b678f583545 100644
--- a/build_config.rb
+++ b/build_config.rb
@@ -13,5 +13,5 @@
 # limitations under the License.
 
 module GrpcBuildConfig
-  CORE_WINDOWS_DLL = '/tmp/libs/opt/grpc-20.dll'
+  CORE_WINDOWS_DLL = '/tmp/libs/opt/grpc-21.dll'
 end
diff --git a/build_handwritten.yaml b/build_handwritten.yaml
index 06b317f8085..c0a963d17eb 100644
--- a/build_handwritten.yaml
+++ b/build_handwritten.yaml
@@ -12,7 +12,7 @@ settings:
   '#08': Use "-preN" suffixes to identify pre-release versions
   '#09': Per-language overrides are possible with (eg) ruby_version tag here
   '#10': See the expand_version.py for all the quirks here
-  core_version: 20.0.0
+  core_version: 21.0.0
   csharp_major_version: 2
   g_stands_for: green
   protobuf_version: 3.18.1
diff --git a/src/core/lib/surface/version.cc b/src/core/lib/surface/version.cc
index 2f09f44d231..64f2829d9dc 100644
--- a/src/core/lib/surface/version.cc
+++ b/src/core/lib/surface/version.cc
@@ -23,6 +23,6 @@
 
 #include <grpc/grpc.h>
 
-const char* grpc_version_string(void) { return "20.0.0"; }
+const char* grpc_version_string(void) { return "21.0.0"; }
 
 const char* grpc_g_stands_for(void) { return "green"; }
diff --git a/src/objective-c/tests/version.h b/src/objective-c/tests/version.h
index f8c6b57e9b4..dff09d4b24f 100644
--- a/src/objective-c/tests/version.h
+++ b/src/objective-c/tests/version.h
@@ -23,4 +23,4 @@
 // `tools/buildgen/generate_projects.sh`.
 
 #define GRPC_OBJC_VERSION_STRING @"1.43.0-dev"
-#define GRPC_C_VERSION_STRING @"20.0.0"
+#define GRPC_C_VERSION_STRING @"21.0.0"
diff --git a/tools/doxygen/Doxyfile.core b/tools/doxygen/Doxyfile.core
index 7ad67d1da24..a2d7dadbb17 100644
--- a/tools/doxygen/Doxyfile.core
+++ b/tools/doxygen/Doxyfile.core
@@ -40,7 +40,7 @@ PROJECT_NAME           = "GRPC Core"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 20.0.0
+PROJECT_NUMBER         = 21.0.0
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index aaeae9016bd..e2ab3c99993 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -40,7 +40,7 @@ PROJECT_NAME           = "GRPC Core"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 20.0.0
+PROJECT_NUMBER         = 21.0.0
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a