diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 84862b855d..99d9e1d60a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -49,15 +49,15 @@ jobs:
         submodules: 'recursive'
     - name: setup
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
       run: |
         sudo -E ./ci/setup_googletest.sh
         sudo -E ./ci/setup_ci_environment.sh
     - name: run cmake tests (without otlp-exporter)
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
       run: |
         ./ci/do_ci.sh cmake.test
 
@@ -297,15 +297,15 @@ jobs:
         submodules: 'recursive'
     - name: setup
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
       run: |
         sudo -E ./ci/setup_googletest.sh
         sudo -E ./ci/setup_ci_environment.sh
     - name: run cmake tests (without otlp-exporter)
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
       run: |
         ./ci/do_ci.sh cmake.with_async_export.test
 
@@ -393,7 +393,7 @@ jobs:
 
   cmake_test_cxx20_clang:
     name: CMake C++20 test(Clang with libc++)
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4
       with:
@@ -443,7 +443,7 @@ jobs:
 
   cmake_test_cxx23_clang:
     name: CMake C++23 test(Clang with libc++)
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4
       with:
@@ -572,15 +572,15 @@ jobs:
         submodules: 'recursive'
     - name: setup
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
       run: |
         sudo -E ./ci/setup_googletest.sh
         sudo -E ./ci/setup_ci_environment.sh
     - name: run tests
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
       run: ./ci/do_ci.sh cmake.test_example_plugin
 
   bazel_test:
@@ -892,7 +892,7 @@ jobs:
 
   code_coverage:
     name: Code coverage
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v4
       with:
@@ -970,8 +970,8 @@ jobs:
           submodules: 'recursive'
       - name: setup
         env:
-          CC: /usr/bin/gcc-10
-          CXX: /usr/bin/g++-10
+          CC: /usr/bin/gcc-12
+          CXX: /usr/bin/g++-12
         run: |
           sudo -E ./ci/setup_googletest.sh
           sudo -E ./ci/setup_ci_environment.sh
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 05acb56180..ebf367e4aa 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -20,8 +20,8 @@ jobs:
         rm -rf third_party
     - name: Setup
       env:
-        CC: /usr/bin/gcc-10
-        CXX: /usr/bin/g++-10
+        CC: /usr/bin/gcc-12
+        CXX: /usr/bin/g++-12
         GOOGLETEST_VERSION: 1.12.1
       run: |
         sudo -E ./ci/setup_googletest.sh
diff --git a/.github/workflows/iwyu.yml b/.github/workflows/iwyu.yml
index 26fdc0f4a7..ad432a78dc 100644
--- a/.github/workflows/iwyu.yml
+++ b/.github/workflows/iwyu.yml
@@ -69,7 +69,7 @@ jobs:
           readonly WARNING_COUNT=`grep -c "include-what-you-use reported diagnostics:" iwyu.log`
           echo "include-what-you-use reported ${WARNING_COUNT} warning(s)"
           # Acceptable limit, to decrease over time down to 0
-          readonly WARNING_LIMIT=10
+          readonly WARNING_LIMIT=180
           # FAIL the build if WARNING_COUNT > WARNING_LIMIT
           if [ $WARNING_COUNT -gt $WARNING_LIMIT ] ; then
             exit 1
diff --git a/api/include/opentelemetry/semconv/error_attributes.h b/api/include/opentelemetry/semconv/error_attributes.h
index 1b711ff112..c68cdeda9f 100644
--- a/api/include/opentelemetry/semconv/error_attributes.h
+++ b/api/include/opentelemetry/semconv/error_attributes.h
@@ -36,9 +36,9 @@ namespace error
  * <p>
  * If the operation has completed successfully, instrumentations SHOULD NOT set @code error.type
  * @endcode. <p> If a specific domain defines its own set of error identifiers (such as HTTP or gRPC
- * status codes), it's RECOMMENDED to: <p> <ul> <li>Use a domain-specific attribute</li> <li>Set
- * @code error.type @endcode to capture all errors, regardless of whether they are defined within
- * the domain-specific set or not.</li>
+ * status codes), it's RECOMMENDED to: <ul> <li>Use a domain-specific attribute</li> <li>Set @code
+ * error.type @endcode to capture all errors, regardless of whether they are defined within the
+ * domain-specific set or not.</li>
  * </ul>
  */
 static constexpr const char *kErrorType = "error.type";
diff --git a/api/include/opentelemetry/semconv/incubating/aws_attributes.h b/api/include/opentelemetry/semconv/incubating/aws_attributes.h
index d0eaa6d08a..b17493879f 100644
--- a/api/include/opentelemetry/semconv/incubating/aws_attributes.h
+++ b/api/include/opentelemetry/semconv/incubating/aws_attributes.h
@@ -247,7 +247,7 @@ static constexpr const char *kAwsS3Bucket = "aws.s3.bucket";
  * The @code copy_source @endcode attribute applies to S3 copy operations and corresponds to the
  * @code --copy-source @endcode parameter of the <a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/copy-object.html">copy-object
- * operation within the S3 API</a>. This applies in particular to the following operations: <p> <ul>
+ * operation within the S3 API</a>. This applies in particular to the following operations: <ul>
  *   <li><a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/copy-object.html">copy-object</a></li>
  *   <li><a
@@ -273,7 +273,7 @@ static constexpr const char *kAwsS3Delete = "aws.s3.delete";
  * <a href="https://docs.aws.amazon.com/cli/latest/reference/s3api/index.html">S3 API</a>
  * operations. <p> The @code key @endcode attribute is applicable to all object-related S3
  * operations, i.e. that require the object key as a mandatory parameter. This applies in particular
- * to the following operations: <p> <ul> <li><a
+ * to the following operations: <ul> <li><a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/copy-object.html">copy-object</a></li>
  *   <li><a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/delete-object.html">delete-object</a></li>
@@ -323,7 +323,7 @@ static constexpr const char *kAwsS3PartNumber = "aws.s3.part_number";
  * The @code upload_id @endcode attribute applies to S3 multipart-upload operations and corresponds
  * to the @code --upload-id @endcode parameter of the <a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/index.html">S3 API</a> multipart
- * operations. This applies in particular to the following operations: <p> <ul> <li><a
+ * operations. This applies in particular to the following operations: <ul> <li><a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/abort-multipart-upload.html">abort-multipart-upload</a></li>
  *   <li><a
  * href="https://docs.aws.amazon.com/cli/latest/reference/s3api/complete-multipart-upload.html">complete-multipart-upload</a></li>
diff --git a/api/include/opentelemetry/semconv/incubating/cloud_attributes.h b/api/include/opentelemetry/semconv/incubating/cloud_attributes.h
index 6720eb3edf..d7a1fe14d0 100644
--- a/api/include/opentelemetry/semconv/incubating/cloud_attributes.h
+++ b/api/include/opentelemetry/semconv/incubating/cloud_attributes.h
@@ -65,7 +65,7 @@ static constexpr const char *kCloudRegion = "cloud.region";
  * startup, so it may be necessary to set @code cloud.resource_id @endcode as a span attribute
  * instead. <p> The exact value to use for @code cloud.resource_id @endcode depends on the cloud
  * provider. The following well-known definitions MUST be used if you set this attribute and they
- * apply: <p> <ul> <li><strong>AWS Lambda:</strong> The function <a
+ * apply: <ul> <li><strong>AWS Lambda:</strong> The function <a
  * href="https://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html">ARN</a>. Take
  * care not to use the "invoked ARN" directly but replace any <a
  * href="https://docs.aws.amazon.com/lambda/latest/dg/configuration-aliases.html">alias suffix</a>
diff --git a/api/include/opentelemetry/semconv/incubating/deployment_attributes.h b/api/include/opentelemetry/semconv/incubating/deployment_attributes.h
index 9c4594b7f3..f6933b4852 100644
--- a/api/include/opentelemetry/semconv/incubating/deployment_attributes.h
+++ b/api/include/opentelemetry/semconv/incubating/deployment_attributes.h
@@ -34,7 +34,7 @@ static constexpr const char *kDeploymentEnvironment = "deployment.environment";
  * @code deployment.environment.name @endcode does not affect the uniqueness constraints defined
  * through the @code service.namespace @endcode, @code service.name @endcode and @code
  * service.instance.id @endcode resource attributes. This implies that resources carrying the
- * following attribute combinations MUST be considered to be identifying the same service: <p> <ul>
+ * following attribute combinations MUST be considered to be identifying the same service: <ul>
  *   <li>@code service.name=frontend @endcode, @code deployment.environment.name=production
  * @endcode</li> <li>@code service.name=frontend @endcode, @code deployment.environment.name=staging
  * @endcode.</li>
diff --git a/api/include/opentelemetry/semconv/incubating/error_attributes.h b/api/include/opentelemetry/semconv/incubating/error_attributes.h
index 1b711ff112..c68cdeda9f 100644
--- a/api/include/opentelemetry/semconv/incubating/error_attributes.h
+++ b/api/include/opentelemetry/semconv/incubating/error_attributes.h
@@ -36,9 +36,9 @@ namespace error
  * <p>
  * If the operation has completed successfully, instrumentations SHOULD NOT set @code error.type
  * @endcode. <p> If a specific domain defines its own set of error identifiers (such as HTTP or gRPC
- * status codes), it's RECOMMENDED to: <p> <ul> <li>Use a domain-specific attribute</li> <li>Set
- * @code error.type @endcode to capture all errors, regardless of whether they are defined within
- * the domain-specific set or not.</li>
+ * status codes), it's RECOMMENDED to: <ul> <li>Use a domain-specific attribute</li> <li>Set @code
+ * error.type @endcode to capture all errors, regardless of whether they are defined within the
+ * domain-specific set or not.</li>
  * </ul>
  */
 static constexpr const char *kErrorType = "error.type";
diff --git a/api/include/opentelemetry/semconv/incubating/faas_attributes.h b/api/include/opentelemetry/semconv/incubating/faas_attributes.h
index ed9076ec39..ade74d610a 100644
--- a/api/include/opentelemetry/semconv/incubating/faas_attributes.h
+++ b/api/include/opentelemetry/semconv/incubating/faas_attributes.h
@@ -58,8 +58,8 @@ static constexpr const char *kFaasDocumentTime = "faas.document.time";
 
 /**
  * The execution environment ID as a string, that will be potentially reused for other invocations
- * to the same function/function version. <p> <ul> <li><strong>AWS Lambda:</strong> Use the (full)
- * log stream name.</li>
+ * to the same function/function version. <ul> <li><strong>AWS Lambda:</strong> Use the (full) log
+ * stream name.</li>
  * </ul>
  */
 static constexpr const char *kFaasInstance = "faas.instance";
@@ -109,7 +109,7 @@ static constexpr const char *kFaasMaxMemory = "faas.max_memory";
  * <a href="/docs/general/attributes.md#source-code-attributes">@code code.namespace @endcode/@code
  * code.function @endcode</a> span attributes). <p> For some cloud providers, the above definition
  * is ambiguous. The following definition of function name MUST be used for this attribute (and
- * consequently the span name) for the listed cloud providers/products: <p> <ul>
+ * consequently the span name) for the listed cloud providers/products: <ul>
  *   <li><strong>Azure:</strong>  The full name @code <FUNCAPP>/<FUNC> @endcode, i.e., function app
  * name followed by a forward slash followed by the function name (this form can also be seen in the
  * resource JSON for the function). This means that a span attribute MUST be used, as an Azure
@@ -135,7 +135,6 @@ static constexpr const char *kFaasTrigger = "faas.trigger";
  * The immutable version of the function being executed.
  * <p>
  * Depending on the cloud provider and platform, use:
- * <p>
  * <ul>
  *   <li><strong>AWS Lambda:</strong> The <a
  * href="https://docs.aws.amazon.com/lambda/latest/dg/configuration-versions.html">function
diff --git a/api/include/opentelemetry/semconv/incubating/hw_metrics.h b/api/include/opentelemetry/semconv/incubating/hw_metrics.h
index 3a87fd2506..d950950f35 100644
--- a/api/include/opentelemetry/semconv/incubating/hw_metrics.h
+++ b/api/include/opentelemetry/semconv/incubating/hw_metrics.h
@@ -132,7 +132,7 @@ static inline nostd::shared_ptr<metrics::ObservableInstrument> CreateAsyncDouble
  * states <p>
  * @code hw.status @endcode is currently specified as an <em>UpDownCounter</em> but would ideally be
  * represented using a <a
- * href="https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#stateset"><em>StateSet</em>
+ * href="https://github.com/prometheus/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#stateset"><em>StateSet</em>
  * as defined in OpenMetrics</a>. This semantic convention will be updated once <em>StateSet</em> is
  * specified in OpenTelemetry. This planned change is not expected to have any consequence on the
  * way users query their timeseries backend to retrieve the values of @code hw.status @endcode over
diff --git a/api/include/opentelemetry/semconv/incubating/system_metrics.h b/api/include/opentelemetry/semconv/incubating/system_metrics.h
index 37ea70a213..1cd5765347 100644
--- a/api/include/opentelemetry/semconv/incubating/system_metrics.h
+++ b/api/include/opentelemetry/semconv/incubating/system_metrics.h
@@ -263,7 +263,7 @@ static inline nostd::shared_ptr<metrics::ObservableInstrument> CreateAsyncDouble
  * Time disk spent activated
  * <p>
  * The real elapsed time ("wall clock") used in the I/O path (time from operations running in
- * parallel are not counted). Measured as: <p> <ul> <li>Linux: Field 13 from <a
+ * parallel are not counted). Measured as: <ul> <li>Linux: Field 13 from <a
  * href="https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats">procfs-diskstats</a></li>
  *   <li>Windows: The complement of
  * <a
@@ -380,7 +380,7 @@ CreateAsyncDoubleMetricSystemDiskMerged(metrics::Meter *meter)
  * Sum of the time each operation took to complete
  * <p>
  * Because it is the sum of time each request took, parallel-issued requests each contribute to make
- * the count grow. Measured as: <p> <ul> <li>Linux: Fields 7 & 11 from <a
+ * the count grow. Measured as: <ul> <li>Linux: Fields 7 & 11 from <a
  * href="https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats">procfs-diskstats</a></li>
  *   <li>Windows: "Avg. Disk sec/Read" perf counter multiplied by "Disk Reads/sec" perf counter
  * (similar for Writes)</li>
@@ -888,7 +888,6 @@ CreateAsyncDoubleMetricSystemNetworkConnections(metrics::Meter *meter)
  * Count of packets that are dropped or discarded even though there was no error
  * <p>
  * Measured as:
- * <p>
  * <ul>
  *   <li>Linux: the @code drop @endcode column in @code /proc/dev/net @endcode (<a
  * href="https://web.archive.org/web/20180321091318/http://www.onlamp.com/pub/a/linux/2000/11/16/LinuxAdmin.html">source</a>)</li>
@@ -937,7 +936,6 @@ CreateAsyncDoubleMetricSystemNetworkDropped(metrics::Meter *meter)
  * Count of network errors detected
  * <p>
  * Measured as:
- * <p>
  * <ul>
  *   <li>Linux: the @code errs @endcode column in @code /proc/dev/net @endcode (<a
  * href="https://web.archive.org/web/20180321091318/http://www.onlamp.com/pub/a/linux/2000/11/16/LinuxAdmin.html">source</a>).</li>
diff --git a/api/include/opentelemetry/semconv/incubating/url_attributes.h b/api/include/opentelemetry/semconv/incubating/url_attributes.h
index 781521fa03..65b78911d7 100644
--- a/api/include/opentelemetry/semconv/incubating/url_attributes.h
+++ b/api/include/opentelemetry/semconv/incubating/url_attributes.h
@@ -59,7 +59,6 @@ static constexpr const char *kUrlFragment = "url.fragment";
  *
  * Query string values for the following keys SHOULD be redacted by default and replaced by the
  * value @code REDACTED @endcode:
- * <p>
  * <ul>
  *   <li><a
  * href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/RESTAuthentication.html#RESTAuthenticationQueryStringAuth">@code
@@ -110,7 +109,7 @@ static constexpr const char *kUrlPort = "url.port";
  * can identify it. <p>
  *
  * Query string values for the following keys SHOULD be redacted by default and replaced by the
- * value @code REDACTED @endcode: <p> <ul> <li><a
+ * value @code REDACTED @endcode: <ul> <li><a
  * href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/RESTAuthentication.html#RESTAuthenticationQueryStringAuth">@code
  * AWSAccessKeyId @endcode</a></li> <li><a
  * href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/RESTAuthentication.html#RESTAuthenticationQueryStringAuth">@code
diff --git a/api/include/opentelemetry/semconv/url_attributes.h b/api/include/opentelemetry/semconv/url_attributes.h
index 9a9c2bb671..17085c5916 100644
--- a/api/include/opentelemetry/semconv/url_attributes.h
+++ b/api/include/opentelemetry/semconv/url_attributes.h
@@ -39,7 +39,6 @@ static constexpr const char *kUrlFragment = "url.fragment";
  *
  * Query string values for the following keys SHOULD be redacted by default and replaced by the
  * value @code REDACTED @endcode:
- * <p>
  * <ul>
  *   <li><a
  * href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/RESTAuthentication.html#RESTAuthenticationQueryStringAuth">@code
@@ -73,7 +72,7 @@ static constexpr const char *kUrlPath = "url.path";
  * can identify it. <p>
  *
  * Query string values for the following keys SHOULD be redacted by default and replaced by the
- * value @code REDACTED @endcode: <p> <ul> <li><a
+ * value @code REDACTED @endcode: <ul> <li><a
  * href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/RESTAuthentication.html#RESTAuthenticationQueryStringAuth">@code
  * AWSAccessKeyId @endcode</a></li> <li><a
  * href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/RESTAuthentication.html#RESTAuthenticationQueryStringAuth">@code
diff --git a/api/test/singleton/CMakeLists.txt b/api/test/singleton/CMakeLists.txt
index 450308cd82..7c30d6e571 100644
--- a/api/test/singleton/CMakeLists.txt
+++ b/api/test/singleton/CMakeLists.txt
@@ -3,59 +3,53 @@
 
 include(GoogleTest)
 
-# Header only singletons are not available in windows yet.
-
-if(NOT WIN32)
-
-  add_library(component_a STATIC component_a.cc)
-  target_link_libraries(component_a opentelemetry_api)
-
-  add_library(component_b STATIC component_b.cc)
-  target_link_libraries(component_b opentelemetry_api)
-
-  add_library(component_c SHARED component_c.cc)
-  set_target_properties(component_c PROPERTIES CXX_VISIBILITY_PRESET default)
-  target_link_libraries(component_c opentelemetry_api)
-
-  add_library(component_d SHARED component_d.cc)
-  set_target_properties(component_d PROPERTIES CXX_VISIBILITY_PRESET hidden)
-  target_link_libraries(component_d opentelemetry_api)
-
-  add_library(component_e SHARED component_e.cc)
-  set_target_properties(component_e PROPERTIES CXX_VISIBILITY_PRESET default)
-  target_link_libraries(component_e opentelemetry_api)
-
-  add_library(component_f SHARED component_f.cc)
-  set_target_properties(component_f PROPERTIES CXX_VISIBILITY_PRESET hidden)
-  target_link_libraries(component_f opentelemetry_api)
-
-  add_library(component_g SHARED component_g.cc)
-  set_target_properties(component_g PROPERTIES CXX_VISIBILITY_PRESET default)
-  target_link_libraries(component_g opentelemetry_api)
-
-  add_library(component_h SHARED component_h.cc)
-  set_target_properties(component_h PROPERTIES CXX_VISIBILITY_PRESET hidden)
-  target_link_libraries(component_h opentelemetry_api)
-
-  add_executable(singleton_test singleton_test.cc)
-
-  # Not linking with component_g and component_h on purpose
-  target_link_libraries(
-    singleton_test
-    component_a
-    component_b
-    component_c
-    component_d
-    component_e
-    component_f
-    ${GTEST_BOTH_LIBRARIES}
-    ${CMAKE_THREAD_LIBS_INIT}
-    ${CMAKE_DL_LIBS}
-    opentelemetry_api)
-
-  gtest_add_tests(
-    TARGET singleton_test
-    TEST_PREFIX singleton.
-    TEST_LIST singleton_test)
-
-endif()
+add_library(component_a STATIC component_a.cc)
+target_link_libraries(component_a opentelemetry_api)
+
+add_library(component_b STATIC component_b.cc)
+target_link_libraries(component_b opentelemetry_api)
+
+add_library(component_c SHARED component_c.cc)
+set_target_properties(component_c PROPERTIES CXX_VISIBILITY_PRESET default)
+target_link_libraries(component_c opentelemetry_api)
+
+add_library(component_d SHARED component_d.cc)
+set_target_properties(component_d PROPERTIES CXX_VISIBILITY_PRESET hidden)
+target_link_libraries(component_d opentelemetry_api)
+
+add_library(component_e SHARED component_e.cc)
+set_target_properties(component_e PROPERTIES CXX_VISIBILITY_PRESET default)
+target_link_libraries(component_e opentelemetry_api)
+
+add_library(component_f SHARED component_f.cc)
+set_target_properties(component_f PROPERTIES CXX_VISIBILITY_PRESET hidden)
+target_link_libraries(component_f opentelemetry_api)
+
+add_library(component_g SHARED component_g.cc)
+set_target_properties(component_g PROPERTIES CXX_VISIBILITY_PRESET default)
+target_link_libraries(component_g opentelemetry_api)
+
+add_library(component_h SHARED component_h.cc)
+set_target_properties(component_h PROPERTIES CXX_VISIBILITY_PRESET hidden)
+target_link_libraries(component_h opentelemetry_api)
+
+add_executable(singleton_test singleton_test.cc)
+
+# Not linking with component_g and component_h on purpose
+target_link_libraries(
+  singleton_test
+  component_a
+  component_b
+  component_c
+  component_d
+  component_e
+  component_f
+  ${GTEST_BOTH_LIBRARIES}
+  ${CMAKE_THREAD_LIBS_INIT}
+  ${CMAKE_DL_LIBS}
+  opentelemetry_api)
+
+gtest_add_tests(
+  TARGET singleton_test
+  TEST_PREFIX singleton.
+  TEST_LIST singleton_test)
diff --git a/api/test/singleton/singleton_test.cc b/api/test/singleton/singleton_test.cc
index d212221118..8b8cb1587d 100644
--- a/api/test/singleton/singleton_test.cc
+++ b/api/test/singleton/singleton_test.cc
@@ -4,12 +4,9 @@
 #include <gtest/gtest.h>
 #include <stdint.h>
 
-/*
-  TODO:
-  Once singleton are supported for windows,
-  expand this test to use ::LoadLibrary, ::GetProcAddress, ::FreeLibrary
-*/
-#ifndef _WIN32
+#ifdef _WIN32
+#  include <windows.h>
+#else
 #  include <dlfcn.h>
 #endif
 
@@ -58,28 +55,57 @@ void do_something()
 #ifndef BAZEL_BUILD
   /* Call do_something_in_g() */
 
+#  ifdef _WIN32
+  HMODULE component_g = LoadLibraryA("component_g.dll");
+#  else
   void *component_g = dlopen("libcomponent_g.so", RTLD_NOW);
+#  endif
+
   EXPECT_NE(component_g, nullptr);
 
+#  ifdef _WIN32
+  auto *func_g = reinterpret_cast<void (*)()>(GetProcAddress(component_g, "do_something_in_g"));
+#  else
   auto *func_g = reinterpret_cast<void (*)()>(dlsym(component_g, "do_something_in_g"));
+#  endif
+
   EXPECT_NE(func_g, nullptr);
 
   (*func_g)();
 
+#  ifdef _WIN32
+  FreeLibrary(component_g);
+#  else
   dlclose(component_g);
+#  endif
 
   /* Call do_something_in_h() */
 
+#  ifdef _WIN32
+  HMODULE component_h = LoadLibraryA("component_h.dll");
+#  else
   void *component_h = dlopen("libcomponent_h.so", RTLD_NOW);
+#  endif
+
   EXPECT_NE(component_h, nullptr);
 
+#  ifdef _WIN32
+  auto *func_h = reinterpret_cast<void (*)()>(GetProcAddress(component_h, "do_something_in_h"));
+#  else
   auto *func_h = reinterpret_cast<void (*)()>(dlsym(component_h, "do_something_in_h"));
+#  endif
+
   EXPECT_NE(func_h, nullptr);
 
   (*func_h)();
 
+#  ifdef _WIN32
+  FreeLibrary(component_h);
+#  else
   dlclose(component_h);
-#endif
+#  endif
+
+#endif /* BAZEL_BUILD */
 }
 
 int span_a_lib_count   = 0;
@@ -316,6 +342,14 @@ void cleanup_otel()
   trace_api::Provider::SetTracerProvider(provider);
 }
 
+// TODO: Remove once windows api singletons are supported.
+// See https://github.com/open-telemetry/opentelemetry-cpp/issues/2534
+#ifdef _WIN32
+#  define RUN_FAILING_WINDOWS_TEST 0
+#else
+#  define RUN_FAILING_WINDOWS_TEST 1
+#endif
+
 TEST(SingletonTest, Uniqueness)
 {
   do_something();
@@ -357,26 +391,31 @@ TEST(SingletonTest, Uniqueness)
   EXPECT_EQ(span_b_lib_count, 1);
   EXPECT_EQ(span_b_f1_count, 2);
   EXPECT_EQ(span_b_f2_count, 1);
-  EXPECT_EQ(span_c_lib_count, 1);
-  EXPECT_EQ(span_c_f1_count, 2);
-  EXPECT_EQ(span_c_f2_count, 1);
-  EXPECT_EQ(span_d_lib_count, 1);
-  EXPECT_EQ(span_d_f1_count, 2);
-  EXPECT_EQ(span_d_f2_count, 1);
-  EXPECT_EQ(span_e_lib_count, 1);
-  EXPECT_EQ(span_e_f1_count, 2);
-  EXPECT_EQ(span_e_f2_count, 1);
-  EXPECT_EQ(span_f_lib_count, 1);
-  EXPECT_EQ(span_f_f1_count, 2);
-  EXPECT_EQ(span_f_f2_count, 1);
+
+#if RUN_FAILING_WINDOWS_TEST
+  EXPECT_EQ(span_c_lib_count, 1);  // Fails with shared libraries on Windows
+  EXPECT_EQ(span_c_f1_count, 2);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_c_f2_count, 1);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_d_lib_count, 1);  // Fails with shared libraries on Windows
+  EXPECT_EQ(span_d_f1_count, 2);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_d_f2_count, 1);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_e_lib_count, 1);  // Fails with shared libraries on Windows
+  EXPECT_EQ(span_e_f1_count, 2);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_e_f2_count, 1);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_f_lib_count, 1);  // Fails with shared libraries on Windows
+  EXPECT_EQ(span_f_f1_count, 2);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_f_f2_count, 1);   // Fails with shared libraries on Windows
+#endif
 
 #ifndef BAZEL_BUILD
-  EXPECT_EQ(span_g_lib_count, 1);
-  EXPECT_EQ(span_g_f1_count, 2);
-  EXPECT_EQ(span_g_f2_count, 1);
-  EXPECT_EQ(span_h_lib_count, 1);
-  EXPECT_EQ(span_h_f1_count, 2);
-  EXPECT_EQ(span_h_f2_count, 1);
+#  if RUN_FAILING_WINDOWS_TEST
+  EXPECT_EQ(span_g_lib_count, 1);  // Fails with shared libraries on Windows
+  EXPECT_EQ(span_g_f1_count, 2);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_g_f2_count, 1);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_h_lib_count, 1);  // Fails with shared libraries on Windows
+  EXPECT_EQ(span_h_f1_count, 2);   // Fails with shared libraries on Windows
+  EXPECT_EQ(span_h_f2_count, 1);   // Fails with shared libraries on Windows
+#  endif
 #endif
 
   EXPECT_EQ(unknown_span_count, 0);
diff --git a/buildscripts/semantic-convention/generate.sh b/buildscripts/semantic-convention/generate.sh
index ac9023d188..f20f5e5af7 100755
--- a/buildscripts/semantic-convention/generate.sh
+++ b/buildscripts/semantic-convention/generate.sh
@@ -19,7 +19,7 @@ ROOT_DIR="${SCRIPT_DIR}/../../"
 SEMCONV_VERSION=1.29.0
 
 # repository: https://github.com/open-telemetry/weaver
-WEAVER_VERSION=0.10.0
+WEAVER_VERSION=0.11.0
 
 SEMCONV_VERSION_TAG=v$SEMCONV_VERSION
 WEAVER_VERSION_TAG=v$WEAVER_VERSION
diff --git a/ci/do_ci.ps1 b/ci/do_ci.ps1
index e9c1f64646..a04ec938f5 100644
--- a/ci/do_ci.ps1
+++ b/ci/do_ci.ps1
@@ -27,6 +27,8 @@ $PLUGIN_DIR = Join-Path "$SRC_DIR" "plugin"
 
 $VCPKG_DIR = Join-Path "$SRC_DIR" "tools" "vcpkg"
 
+$Env:CTEST_OUTPUT_ON_FAILURE = "1"
+
 switch ($action) {
   "bazel.build" {
     bazel $BAZEL_STARTUP_OPTIONS build $BAZEL_OPTIONS --action_env=VCPKG_DIR=$VCPKG_DIR --deleted_packages=opentracing-shim -- //...
diff --git a/docs/maintaining-dependencies.md b/docs/maintaining-dependencies.md
index 31a50db521..f213e653ca 100644
--- a/docs/maintaining-dependencies.md
+++ b/docs/maintaining-dependencies.md
@@ -14,6 +14,13 @@ Also, another good place to start when upgrading something to N+1
 is to find the commit that upgraded to version N (use `git blame`),
 and inspect the commit for the last upgrade.
 
+## Overview
+
+|      Dependency      |      Type     |
+| -------------------- | ------------- |
+| opentelemetry-proto  | git submodule |
+|    prometheus-cpp    | git submodule |
+
 ## opentelemetry-proto
 
 ### Comments (opentelemetry-proto)
@@ -49,71 +56,8 @@ In this example, we upgrade from 1.3.1 to 1.3.2
 
 #### directory third_party/opentelemetry-proto
 
-This is a `git submodule`, it needs to point to the new tag.
-
-```shell
-cd third_party/opentelemetry-proto
-git log -1
-```
-
-The current submodule show something like:
-
-```shell
-commit b3060d2104df364136d75a35779e6bd48bac449a (HEAD, tag: v1.3.1)
-Author: Damien Mathieu <42@dmathieu.com>
-Date:   Thu Apr 25 17:55:35 2024 +0200
-
-    generate profiles proto for CI (#552)
-```
-
-Pull new tags:
-
-```shell
-git pull --tag origin
-```
-
-Upgrade to a new tag:
-
-```shell
-git pull origin v1.3.2
-```
-
-Check the new state:
-
-```shell
-git log -1
-```
-
-```shell
-commit 40b3c1b746767cbc13c2e39da3eaf1a23e54ffdd (HEAD, tag: v1.3.2)
-Author: jack-berg <34418638+jack-berg@users.noreply.github.com>
-Date:   Fri Jun 28 08:19:11 2024 -0500
-
-    Prepare changelog for 1.3.2 release (#563)
-
-    Co-authored-by: Armin Ruech <7052238+arminru@users.noreply.github.com>
-```
-
-Go back to the root of opentelemetry-cpp
-
-```shell
-cd ../..
-git status
-```
-
-```shell
-On branch upgrade_proto_1.3.2
-Changes not staged for commit:
-  (use "git add <file>..." to update what will be committed)
-  (use "git restore <file>..." to discard changes in working directory)
-        modified:   third_party/opentelemetry-proto (new commits)
-```
-
-Add the upgraded submodule:
-
-```shell
-git add third_party/opentelemetry-proto
-```
+You need to update the git submodule third_party/opentelemetry-proto,
+check [Upgrade a git submodule](#upgrade-a-git-submodule) for more details.
 
 #### file third_party_release
 
@@ -144,80 +88,8 @@ index 0bbf67f3..7362473f 100644
 
 #### file bazel/repository.bzl
 
-Locate the entry for opentelemetry-proto:
-
-```text
-    # OTLP Protocol definition
-    maybe(
-        http_archive,
-        name = "com_github_opentelemetry_proto",
-        build_file = "@io_opentelemetry_cpp//bazel:opentelemetry_proto.BUILD",
-        sha256 = "bed250ceec8e4a83aa5604d7d5595a61945059dc662edd058a9da082283f7a00",
-        strip_prefix = "opentelemetry-proto-1.3.1",
-        urls = [
-            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.1.tar.gz",
-        ],
-    )
-```
-
-Update the URL to the new tag:
-
-```text
-        urls = [
-            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz",
-        ],
-```
-
-Update strip_prefix to the new tag:
-
-```text
-        strip_prefix = "opentelemetry-proto-1.3.2",
-```
-
-Download the new URL:
-
-```shell
-wget https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz
-```
-
-Run a checksum on the new file:
-
-```shell
-sha256sum v1.3.2.tar.gz
-```
-
-```shell
-c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7  v1.3.2.tar.gz
-```
-
-Update the checksum in file bazel/repository.bzl:
-
-```text
-        sha256 = "c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7",
-```
-
-Typical change:
-
-```shell
-[malff@malff-desktop opentelemetry-cpp]$ git diff bazel/repository.bzl
-diff --git a/bazel/repository.bzl b/bazel/repository.bzl
-index bac1e45b..508b95a3 100644
---- a/bazel/repository.bzl
-+++ b/bazel/repository.bzl
-@@ -88,10 +88,10 @@ def opentelemetry_cpp_deps():
-         http_archive,
-         name = "com_github_opentelemetry_proto",
-         build_file = "@io_opentelemetry_cpp//bazel:opentelemetry_proto.BUILD",
--        sha256 = "bed250ceec8e4a83aa5604d7d5595a61945059dc662edd058a9da082283f7a00",
--        strip_prefix = "opentelemetry-proto-1.3.1",
-+        sha256 = "c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7",
-+        strip_prefix = "opentelemetry-proto-1.3.2",
-         urls = [
--            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.1.tar.gz",
-+            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz",
-         ],
-     )
-```
+Please follow the guide [Upgrade a bazel dependency](#upgrade-a-bazel-dependency)
+for more details.
 
 #### file cmake/opentelemetry-proto.cmake
 
@@ -269,47 +141,6 @@ In this case, it is better to:
 When the C++ code requires a newer minimum version of opentelemetry-proto,
 make sure to document this, including in the release notes.
 
-#### file MODULE.bazel
-
-Make sure the new tag is available in bazel central:
-
-* [bazel-central](https://registry.bazel.build/modules/opentelemetry-proto)
-
-If missing, file a PR to add it, or contact the maintainer:
-
-* [repository](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/opentelemetry-proto)
-
-Update the opentelemetry-proto version to the new tag:
-
-```text
-bazel_dep(name = "opentelemetry-proto", version = "1.3.2", repo_name = "com_github_opentelemetry_proto")
-```
-
-File `MODULE.bazel` is used in the github CI for repository
-opentelemetry-cpp, so using a tag that does not exist (yet) in bazel central
-will break the CI build.
-
-See the known issues section.
-
-Typical change:
-
-```shell
-[malff@malff-desktop opentelemetry-cpp]$ git diff MODULE.bazel
-diff --git a/MODULE.bazel b/MODULE.bazel
-index 7b84c2b7..3161ffb1 100644
---- a/MODULE.bazel
-+++ b/MODULE.bazel
-@@ -13,7 +13,7 @@ bazel_dep(name = "bazel_skylib", version = "1.5.0")
- bazel_dep(name = "curl", version = "8.4.0")
- bazel_dep(name = "grpc", version = "1.62.1", repo_name = "com_github_grpc_grpc")
- bazel_dep(name = "nlohmann_json", version = "3.11.3", repo_name = "github_nlohmann_json")
--bazel_dep(name = "opentelemetry-proto", version = "1.3.1", repo_name = "com_github_opentelemetry_proto")
-+bazel_dep(name = "opentelemetry-proto", version = "1.3.2", repo_name = "com_github_opentelemetry_proto")
- bazel_dep(name = "opentracing-cpp", version = "1.6.0", repo_name = "com_github_opentracing")
- bazel_dep(name = "platforms", version = "0.0.8")
- bazel_dep(name = "prometheus-cpp", version = "1.2.4", repo_name = "com_github_jupp0r_prometheus_cpp")
-```
-
 ### Known issues (opentelemetry-proto)
 
 For bazel, two different methods to build exists.
@@ -599,3 +430,209 @@ abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234  v1.2.4.tar.gz
 ```
 
 Update the `sha256`.
+
+## Upgrade a git submodule
+
+All the git submodule are under the folder `third_party`.
+We will use `opentelemetry-propto` as example in this case.
+This is a `git submodule`, it needs to point to the new tag.
+
+### Get current tag
+
+```shell
+cd third_party/opentelemetry-proto
+git log -1
+```
+
+The current submodule show something like:
+
+```shell
+commit b3060d2104df364136d75a35779e6bd48bac449a (HEAD, tag: v1.3.1)
+Author: Damien Mathieu <42@dmathieu.com>
+Date:   Thu Apr 25 17:55:35 2024 +0200
+
+    generate profiles proto for CI (#552)
+```
+
+In this case we can see the current tag is `v.1.3.1`.
+
+### Upgrade to new tag
+
+Pull new tags:
+
+```shell
+git pull --tag origin
+```
+
+Upgrade to a new tag:
+
+```shell
+git pull origin v1.3.2
+```
+
+Check the new state:
+
+```shell
+git log -1
+```
+
+```shell
+commit 40b3c1b746767cbc13c2e39da3eaf1a23e54ffdd (HEAD, tag: v1.3.2)
+Author: jack-berg <34418638+jack-berg@users.noreply.github.com>
+Date:   Fri Jun 28 08:19:11 2024 -0500
+
+    Prepare changelog for 1.3.2 release (#563)
+
+    Co-authored-by: Armin Ruech <7052238+arminru@users.noreply.github.com>
+```
+
+### Add changes
+
+Go back to the root of opentelemetry-cpp
+
+```shell
+cd ../..
+git status
+```
+
+```shell
+On branch upgrade_proto_1.3.2
+Changes not staged for commit:
+  (use "git add <file>..." to update what will be committed)
+  (use "git restore <file>..." to discard changes in working directory)
+        modified:   third_party/opentelemetry-proto (new commits)
+```
+
+Add the upgraded submodule:
+
+```shell
+git add third_party/opentelemetry-proto
+```
+
+## Upgrade a bazel dependency
+
+Same as git submodule, we will continue use `opentelemetry-proto` as example.
+
+All the bazel dependencies are defined in [repository.bzl](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/bazel/repository.bzl)
+and [MODULE.bazel](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/MODULE.bazel).
+
+### Update the dependency in repository.bzl
+
+Locate the entry for opentelemetry-proto:
+
+```text
+    # OTLP Protocol definition
+    maybe(
+        http_archive,
+        name = "com_github_opentelemetry_proto",
+        build_file = "@io_opentelemetry_cpp//bazel:opentelemetry_proto.BUILD",
+        sha256 = "bed250ceec8e4a83aa5604d7d5595a61945059dc662edd058a9da082283f7a00",
+        strip_prefix = "opentelemetry-proto-1.3.1",
+        urls = [
+            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.1.tar.gz",
+        ],
+    )
+```
+
+Update the URL to the new tag:
+
+```text
+        urls = [
+            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz",
+        ],
+```
+
+Update strip_prefix to the new tag:
+
+```text
+        strip_prefix = "opentelemetry-proto-1.3.2",
+```
+
+Download the new URL:
+
+```shell
+wget https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz
+```
+
+Run a checksum on the new file:
+
+```shell
+sha256sum v1.3.2.tar.gz
+```
+
+```shell
+c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7  v1.3.2.tar.gz
+```
+
+Update the checksum in file bazel/repository.bzl:
+
+```text
+        sha256 = "c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7",
+```
+
+Typical change:
+
+```shell
+[malff@malff-desktop opentelemetry-cpp]$ git diff bazel/repository.bzl
+diff --git a/bazel/repository.bzl b/bazel/repository.bzl
+index bac1e45b..508b95a3 100644
+--- a/bazel/repository.bzl
++++ b/bazel/repository.bzl
+@@ -88,10 +88,10 @@ def opentelemetry_cpp_deps():
+         http_archive,
+         name = "com_github_opentelemetry_proto",
+         build_file = "@io_opentelemetry_cpp//bazel:opentelemetry_proto.BUILD",
+-        sha256 = "bed250ceec8e4a83aa5604d7d5595a61945059dc662edd058a9da082283f7a00",
+-        strip_prefix = "opentelemetry-proto-1.3.1",
++        sha256 = "c069c0d96137cf005d34411fa67dd3b6f1f8c64af1e7fb2fe0089a41c425acd7",
++        strip_prefix = "opentelemetry-proto-1.3.2",
+         urls = [
+-            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.1.tar.gz",
++            "https://github.com/open-telemetry/opentelemetry-proto/archive/v1.3.2.tar.gz",
+         ],
+     )
+```
+
+#### Update MODULE.bazel
+
+> Remember, the link is different in your case.
+Replace `opentelemetry-proto` to correct target.
+
+Make sure the new tag is available in bazel central:
+
+* [opentelemetry-proto bazel-central](https://registry.bazel.build/modules/opentelemetry-proto)
+
+If missing, file a PR to add it, or contact the maintainer:
+
+* [opentelemetry-proto repository](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/opentelemetry-proto)
+
+Update the `opentelemetry-proto` version to the new tag:
+
+```text
+bazel_dep(name = "opentelemetry-proto", version = "1.3.2", repo_name = "com_github_opentelemetry_proto")
+```
+
+File `MODULE.bazel` is used in the github CI for repository
+opentelemetry-cpp, so using a tag that does not exist (yet) in bazel central
+will break the CI build.
+
+See the known issues section.
+
+Typical change:
+
+```shell
+[malff@malff-desktop opentelemetry-cpp]$ git diff MODULE.bazel
+diff --git a/MODULE.bazel b/MODULE.bazel
+index 7b84c2b7..3161ffb1 100644
+--- a/MODULE.bazel
++++ b/MODULE.bazel
+@@ -13,7 +13,7 @@ bazel_dep(name = "bazel_skylib", version = "1.5.0")
+ bazel_dep(name = "curl", version = "8.4.0")
+ bazel_dep(name = "grpc", version = "1.62.1", repo_name = "com_github_grpc_grpc")
+ bazel_dep(name = "nlohmann_json", version = "3.11.3", repo_name = "github_nlohmann_json")
+-bazel_dep(name = "opentelemetry-proto", version = "1.3.1", repo_name = "com_github_opentelemetry_proto")
++bazel_dep(name = "opentelemetry-proto", version = "1.3.2", repo_name = "com_github_opentelemetry_proto")
+ bazel_dep(name = "opentracing-cpp", version = "1.6.0", repo_name = "com_github_opentracing")
+ bazel_dep(name = "platforms", version = "0.0.8")
+ bazel_dep(name = "prometheus-cpp", version = "1.2.4", repo_name = "com_github_jupp0r_prometheus_cpp")
+```
diff --git a/exporters/otlp/test/otlp_recordable_test.cc b/exporters/otlp/test/otlp_recordable_test.cc
index 1fdcf00217..8309811ae0 100644
--- a/exporters/otlp/test/otlp_recordable_test.cc
+++ b/exporters/otlp/test/otlp_recordable_test.cc
@@ -136,6 +136,7 @@ TEST(OtlpRecordable, SetInstrumentationScopeWithAttributes)
 
   ASSERT_EQ(proto_instr_libr.attributes_size(), 1);
   const auto &proto_attributes = proto_instr_libr.attributes(0);
+  // Requires protoc 3.15.0
   // ASSERT_TRUE(proto_attributes.value().has_string_value());
   EXPECT_EQ("test_key", proto_attributes.key());
   EXPECT_EQ("test_value", proto_attributes.value().string_value());
diff --git a/ext/test/http/curl_http_test.cc b/ext/test/http/curl_http_test.cc
index 137c9b7f9b..1b4289f400 100644
--- a/ext/test/http/curl_http_test.cc
+++ b/ext/test/http/curl_http_test.cc
@@ -33,7 +33,7 @@ class CustomEventHandler : public http_client::EventHandler
 public:
   void OnResponse(http_client::Response & /* response */) noexcept override
   {
-    got_response_ = true;
+    got_response_.store(true, std::memory_order_release);
   }
   void OnEvent(http_client::SessionState state, nostd::string_view /* reason */) noexcept override
   {
@@ -41,16 +41,20 @@ class CustomEventHandler : public http_client::EventHandler
     {
       case http_client::SessionState::ConnectFailed:
       case http_client::SessionState::SendFailed: {
-        is_called_ = true;
+        is_called_.store(true, std::memory_order_release);
         break;
       }
       default:
         break;
     }
   }
+
+  CustomEventHandler() : is_called_(false), got_response_(false) {}
+
   ~CustomEventHandler() override = default;
-  bool is_called_                = false;
-  bool got_response_             = false;
+
+  std::atomic<bool> is_called_;
+  std::atomic<bool> got_response_;
 };
 
 class GetEventHandler : public CustomEventHandler
@@ -59,8 +63,8 @@ class GetEventHandler : public CustomEventHandler
   {
     ASSERT_EQ(200, response.GetStatusCode());
     ASSERT_EQ(response.GetBody().size(), 0);
-    is_called_    = true;
-    got_response_ = true;
+    is_called_.store(true, std::memory_order_release);
+    got_response_.store(true, std::memory_order_release);
   }
 };
 
@@ -71,8 +75,8 @@ class PostEventHandler : public CustomEventHandler
     ASSERT_EQ(200, response.GetStatusCode());
     std::string body(response.GetBody().begin(), response.GetBody().end());
     ASSERT_EQ(body, "{'k1':'v1', 'k2':'v2', 'k3':'v3'}");
-    is_called_    = true;
-    got_response_ = true;
+    is_called_.store(true, std::memory_order_release);
+    got_response_.store(true, std::memory_order_release);
   }
 };
 
@@ -87,8 +91,8 @@ class FinishInCallbackHandler : public CustomEventHandler
   {
     ASSERT_EQ(200, response.GetStatusCode());
     ASSERT_EQ(response.GetBody().size(), 0);
-    is_called_    = true;
-    got_response_ = true;
+    is_called_.store(true, std::memory_order_release);
+    got_response_.store(true, std::memory_order_release);
 
     if (session_)
     {
@@ -249,8 +253,8 @@ TEST_F(BasicCurlHttpTests, SendGetRequest)
   session->SendRequest(handler);
   ASSERT_TRUE(waitForRequests(30, 1));
   session->FinishSession();
-  ASSERT_TRUE(handler->is_called_);
-  ASSERT_TRUE(handler->got_response_);
+  ASSERT_TRUE(handler->is_called_.load(std::memory_order_acquire));
+  ASSERT_TRUE(handler->got_response_.load(std::memory_order_acquire));
 }
 
 TEST_F(BasicCurlHttpTests, SendPostRequest)
@@ -272,8 +276,8 @@ TEST_F(BasicCurlHttpTests, SendPostRequest)
   session->SendRequest(handler);
   ASSERT_TRUE(waitForRequests(30, 1));
   session->FinishSession();
-  ASSERT_TRUE(handler->is_called_);
-  ASSERT_TRUE(handler->got_response_);
+  ASSERT_TRUE(handler->is_called_.load(std::memory_order_acquire));
+  ASSERT_TRUE(handler->got_response_.load(std::memory_order_acquire));
 
   session_manager->CancelAllSessions();
   session_manager->FinishAllSessions();
@@ -291,8 +295,8 @@ TEST_F(BasicCurlHttpTests, RequestTimeout)
   auto handler = std::make_shared<GetEventHandler>();
   session->SendRequest(handler);
   session->FinishSession();
-  ASSERT_TRUE(handler->is_called_);
-  ASSERT_FALSE(handler->got_response_);
+  ASSERT_TRUE(handler->is_called_.load(std::memory_order_acquire));
+  ASSERT_FALSE(handler->got_response_.load(std::memory_order_acquire));
 }
 
 TEST_F(BasicCurlHttpTests, CurlHttpOperations)
@@ -408,8 +412,8 @@ TEST_F(BasicCurlHttpTests, SendGetRequestAsync)
       sessions[i]->FinishSession();
       ASSERT_FALSE(sessions[i]->IsSessionActive());
 
-      ASSERT_TRUE(handlers[i]->is_called_);
-      ASSERT_TRUE(handlers[i]->got_response_);
+      ASSERT_TRUE(handlers[i]->is_called_.load(std::memory_order_acquire));
+      ASSERT_TRUE(handlers[i]->got_response_.load(std::memory_order_acquire));
     }
 
     http_client.WaitBackgroundThreadExit();
@@ -437,7 +441,8 @@ TEST_F(BasicCurlHttpTests, SendGetRequestAsyncTimeout)
     // Lock mtx_requests to prevent response, we will check IsSessionActive() in the end
     std::unique_lock<std::mutex> lock_requests(mtx_requests);
     sessions[i]->SendRequest(handlers[i]);
-    ASSERT_TRUE(sessions[i]->IsSessionActive() || handlers[i]->is_called_);
+    ASSERT_TRUE(sessions[i]->IsSessionActive() ||
+                handlers[i]->is_called_.load(std::memory_order_acquire));
   }
 
   for (unsigned i = 0; i < batch_count; ++i)
@@ -445,8 +450,8 @@ TEST_F(BasicCurlHttpTests, SendGetRequestAsyncTimeout)
     sessions[i]->FinishSession();
     ASSERT_FALSE(sessions[i]->IsSessionActive());
 
-    ASSERT_TRUE(handlers[i]->is_called_);
-    ASSERT_FALSE(handlers[i]->got_response_);
+    ASSERT_TRUE(handlers[i]->is_called_.load(std::memory_order_acquire));
+    ASSERT_FALSE(handlers[i]->got_response_.load(std::memory_order_acquire));
   }
 }
 
@@ -482,8 +487,8 @@ TEST_F(BasicCurlHttpTests, SendPostRequestAsync)
       ASSERT_FALSE(session->IsSessionActive());
     }
 
-    ASSERT_TRUE(handler->is_called_);
-    ASSERT_TRUE(handler->got_response_);
+    ASSERT_TRUE(handler->is_called_.load(std::memory_order_acquire));
+    ASSERT_TRUE(handler->got_response_.load(std::memory_order_acquire));
 
     http_client.WaitBackgroundThreadExit();
   }
@@ -521,8 +526,8 @@ TEST_F(BasicCurlHttpTests, FinishInAsyncCallback)
     {
       ASSERT_FALSE(sessions[i]->IsSessionActive());
 
-      ASSERT_TRUE(handlers[i]->is_called_);
-      ASSERT_TRUE(handlers[i]->got_response_);
+      ASSERT_TRUE(handlers[i]->is_called_.load(std::memory_order_acquire));
+      ASSERT_TRUE(handlers[i]->got_response_.load(std::memory_order_acquire));
     }
   }
 }