diff --git a/.bazelrc b/.bazelrc
index 1f43fc9c4..d4447811b 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -37,7 +37,6 @@ build:minimal --@io_bazel_rules_go//go/config:tags=minimal
 
 # Release flags
 build:release --compilation_mode=opt
-build:release --config=llvm
 
 # LLVM compiler for building C/C++ dependencies.
 build:llvm --define compiler=llvm
diff --git a/tools/cross-toolchain/configs/.latest.bazelrc b/tools/cross-toolchain/configs/.latest.bazelrc
index cd5888b61..44e6c707d 100644
--- a/tools/cross-toolchain/configs/.latest.bazelrc
+++ b/tools/cross-toolchain/configs/.latest.bazelrc
@@ -19,13 +19,13 @@
 # Specifically, it includes all toolchain/platform flags
 # This file is used for testing purposes.
 
-build:remote --host_javabase=//tools/cross-toolchain/configs/clang/bazel_5.0.0/java:jdk
-build:remote --javabase=//tools/cross-toolchain/configs/clang/bazel_5.0.0/java:jdk
-build:remote --crosstool_top=//tools/cross-toolchain/configs/clang/bazel_5.0.0/cc:toolchain
-build:remote --extra_toolchains=//tools/cross-toolchain/configs/clang/bazel_5.0.0/config:cc-toolchain
-build:remote --extra_execution_platforms=//tools/cross-toolchain/configs/clang/bazel_5.0.0/config:platform
-build:remote --host_platform=//tools/cross-toolchain/configs/clang/bazel_5.0.0/config:platform
-build:remote --platforms=//tools/cross-toolchain/configs/clang/bazel_5.0.0/config:platform
+build:remote --host_javabase=//tools/cross-toolchain/configs/clang/bazel_5.3.0/java:jdk
+build:remote --javabase=//tools/cross-toolchain/configs/clang/bazel_5.3.0/java:jdk
+build:remote --crosstool_top=//tools/cross-toolchain/configs/clang/bazel_5.3.0/cc:toolchain
+build:remote --extra_toolchains=//tools/cross-toolchain/configs/clang/bazel_5.3.0/config:cc-toolchain
+build:remote --extra_execution_platforms=//tools/cross-toolchain/configs/clang/bazel_5.3.0/config:platform
+build:remote --host_platform=//tools/cross-toolchain/configs/clang/bazel_5.3.0/config:platform
+build:remote --platforms=//tools/cross-toolchain/configs/clang/bazel_5.3.0/config:platform
 
 # Import the default bazelrc file in bazel-toolchains repo.
 # This will only work for tests executed from bazel-toolchains
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/BUILD b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/BUILD
similarity index 99%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/BUILD
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/BUILD
index 7b1615144..c58ce8725 100755
--- a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/BUILD
+++ b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/BUILD
@@ -84,7 +84,6 @@ cc_toolchain_config(
     abi_libc_version = "local",
     abi_version = "local",
     compile_flags = [
-        "-U_FORTIFY_SOURCE",
         "-fstack-protector",
         "-Wall",
         "-Wthread-safety",
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/armeabi_cc_toolchain_config.bzl b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/armeabi_cc_toolchain_config.bzl
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/armeabi_cc_toolchain_config.bzl
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/armeabi_cc_toolchain_config.bzl
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/builtin_include_directory_paths b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/builtin_include_directory_paths
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/builtin_include_directory_paths
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/builtin_include_directory_paths
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/cc_toolchain_config.bzl b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/cc_toolchain_config.bzl
similarity index 96%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/cc_toolchain_config.bzl
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/cc_toolchain_config.bzl
index 261191410..0b77afcb7 100755
--- a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/cc_toolchain_config.bzl
+++ b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/cc_toolchain_config.bzl
@@ -173,6 +173,21 @@ def _impl(ctx):
         name = "default_compile_flags",
         enabled = True,
         flag_sets = [
+            flag_set(
+                actions = all_compile_actions,
+                flag_groups = [
+                    flag_group(
+                        # Security hardening requires optimization.
+                        # We need to undef it as some distributions now have it enabled by default.
+                        flags = ["-U_FORTIFY_SOURCE"],
+                    ),
+                ],
+                with_features = [
+                    with_feature_set(
+                        not_features = ["thin_lto"],
+                    ),
+                ],
+            ),
             flag_set(
                 actions = all_compile_actions,
                 flag_groups = ([
@@ -1049,6 +1064,31 @@ def _impl(ctx):
         ],
     )
 
+    serialized_diagnostics_file_feature = feature(
+        name = "serialized_diagnostics_file",
+        flag_sets = [
+            flag_set(
+                actions = [
+                    ACTION_NAMES.assemble,
+                    ACTION_NAMES.preprocess_assemble,
+                    ACTION_NAMES.c_compile,
+                    ACTION_NAMES.cpp_compile,
+                    ACTION_NAMES.cpp_module_compile,
+                    ACTION_NAMES.objc_compile,
+                    ACTION_NAMES.objcpp_compile,
+                    ACTION_NAMES.cpp_header_parsing,
+                    ACTION_NAMES.clif_match,
+                ],
+                flag_groups = [
+                    flag_group(
+                        flags = ["--serialize-diagnostics", "%{serialized_diagnostics_file}"],
+                        expand_if_available = "serialized_diagnostics_file",
+                    ),
+                ],
+            ),
+        ],
+    )
+
     dynamic_library_linker_tool_path = tool_paths
     dynamic_library_linker_tool_feature = feature(
         name = "dynamic_library_linker_tool",
@@ -1187,6 +1227,7 @@ def _impl(ctx):
     if is_linux:
         features = [
             dependency_file_feature,
+            serialized_diagnostics_file_feature,
             random_seed_feature,
             pic_feature,
             per_object_debug_info_feature,
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/cc_wrapper.sh b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/cc_wrapper.sh
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/cc_wrapper.sh
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/cc_wrapper.sh
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/module.modulemap b/tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/module.modulemap
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/cc/module.modulemap
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/cc/module.modulemap
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/config/BUILD b/tools/cross-toolchain/configs/clang/bazel_5.3.0/config/BUILD
similarity index 96%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/config/BUILD
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/config/BUILD
index 33abfdcce..f5fde854d 100644
--- a/tools/cross-toolchain/configs/clang/bazel_5.0.0/config/BUILD
+++ b/tools/cross-toolchain/configs/clang/bazel_5.3.0/config/BUILD
@@ -29,7 +29,7 @@ toolchain(
         "@bazel_tools//platforms:linux",
         "@bazel_tools//platforms:x86_64",
     ],
-    toolchain = "//tools/cross-toolchain/configs/clang/bazel_5.0.0/cc:cc-compiler-k8",
+    toolchain = "//tools/cross-toolchain/configs/clang/bazel_5.3.0/cc:cc-compiler-k8",
     toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
 )
 
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/java/BUILD b/tools/cross-toolchain/configs/clang/bazel_5.3.0/java/BUILD
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/java/BUILD
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/java/BUILD
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/BUILD.bazel b/tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/BUILD.bazel
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/BUILD.bazel
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/BUILD.bazel
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/WORKSPACE b/tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/WORKSPACE
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/WORKSPACE
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/WORKSPACE
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/cc_toolchain_config_linux_arm64.bzl b/tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/cc_toolchain_config_linux_arm64.bzl
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/cc_toolchain_config_linux_arm64.bzl
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/cc_toolchain_config_linux_arm64.bzl
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/cc_toolchain_config_osx.bzl b/tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/cc_toolchain_config_osx.bzl
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/cc_toolchain_config_osx.bzl
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/cc_toolchain_config_osx.bzl
diff --git a/tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/cc_toolchain_config_windows.bzl b/tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/cc_toolchain_config_windows.bzl
similarity index 100%
rename from tools/cross-toolchain/configs/clang/bazel_5.0.0/prysm_toolchains/cc_toolchain_config_windows.bzl
rename to tools/cross-toolchain/configs/clang/bazel_5.3.0/prysm_toolchains/cc_toolchain_config_windows.bzl
diff --git a/tools/cross-toolchain/configs/versions.bzl b/tools/cross-toolchain/configs/versions.bzl
index 521db923e..8b628468c 100644
--- a/tools/cross-toolchain/configs/versions.bzl
+++ b/tools/cross-toolchain/configs/versions.bzl
@@ -3,7 +3,7 @@
 """Definitions to be used in rbe_repo attr of an rbe_autoconf rule  """
 toolchain_config_spec0 = struct(config_repos = ["prysm_toolchains"], create_cc_configs = True, create_java_configs = True, env = {"BAZEL_COMPILER": "clang", "BAZEL_LINKLIBS": "-l%:libstdc++.a", "BAZEL_LINKOPTS": "-lm:-static-libgcc", "BAZEL_USE_LLVM_NATIVE_COVERAGE": "1", "GCOV": "llvm-profdata", "CC": "clang", "CXX": "clang++"}, java_home = "/usr/lib/jvm/java-8-openjdk-amd64", name = "clang")
 _TOOLCHAIN_CONFIG_SPECS = [toolchain_config_spec0]
-_BAZEL_TO_CONFIG_SPEC_NAMES = {"5.0.0": ["clang"]}
+_BAZEL_TO_CONFIG_SPEC_NAMES = {"5.3.0": ["clang"]}
 LATEST = "sha256:9e04c71268adeb4028b4016ca8cc02d134c2e5d7e3a53fdc68154d1797bb3d70"
 CONTAINER_TO_CONFIG_SPEC_NAMES = {"sha256:9e04c71268adeb4028b4016ca8cc02d134c2e5d7e3a53fdc68154d1797bb3d70": ["clang"]}
 _DEFAULT_TOOLCHAIN_CONFIG_SPEC = toolchain_config_spec0