diff --git a/docker/Dockerfile.centos b/docker/Dockerfile.centos
index 66ca8f24b3..66138ba60a 100644
--- a/docker/Dockerfile.centos
+++ b/docker/Dockerfile.centos
@@ -1,13 +1,15 @@
 FROM centos:7
 
+ARG TOOLSET_VER=11
+
 RUN yum update -y && yum install -y centos-release-scl epel-release
-RUN yum install -y devtoolset-11 \
+RUN yum install -y devtoolset-${TOOLSET_VER} \
     cmake3 git \
     openssl-devel \
     libcurl-devel \
-    && source /opt/rh/devtoolset-11/enable
+    && source /opt/rh/devtoolset-${TOOLSET_VER}/enable
 
-RUN echo "source /opt/rh/devtoolset-11/enable" >> /etc/bashrc
+RUN echo "source /opt/rh/devtoolset-${TOOLSET_VER}/enable" >> /etc/bashrc
 RUN echo "BOOST_LIBRARYDIR=/usr/lib64/boost169" >> /etc/bashrc
 RUN echo "BOOST_INCLUDEDIR=/usr/include/boost169" >> /etc/bashrc
 
@@ -17,7 +19,7 @@ ARG GRPC_VERSION=v1.43.2
 RUN git clone --depth=1 -b $GRPC_VERSION  https://github.com/grpc/grpc.git \
     && cd grpc && git submodule update --init \
     && mkdir -p "third_party/abseil-cpp/build" && cd "third_party/abseil-cpp/build" \
-    && source /opt/rh/devtoolset-11/enable \
+    && source /opt/rh/devtoolset-${TOOLSET_VER}/enable \
     && cmake3 -DCMAKE_CXX_STANDARD=17 -DCMAKE_BUILD_TYPE=Release -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE .. \
     && make -j${nproc} install && cd ../../.. \
     && mkdir build && cd build \
@@ -40,7 +42,7 @@ RUN yum install -y \
     && wget https://github.com/apache/thrift/archive/refs/tags/v$THRIFT_VERSION.tar.gz \
     && tar -xvf v$THRIFT_VERSION.tar.gz \
     && mkdir -p thrift-$THRIFT_VERSION/build && cd thrift-$THRIFT_VERSION/build \
-    && source /opt/rh/devtoolset-11/enable \
+    && source /opt/rh/devtoolset-${TOOLSET_VER}/enable \
     && export BOOST_INCLUDEDIR=/usr/include/boost169 \
     && export BOOST_LIBRARYDIR=/usr/lib64/boost169 \
     && cmake3 \
@@ -66,7 +68,7 @@ RUN yum install -y \
 RUN git clone --depth=1 https://github.com/open-telemetry/opentelemetry-cpp.git \
     && cd opentelemetry-cpp && git submodule update --init \
     && mkdir -p build && cd build \
-    && source /opt/rh/devtoolset-11/enable \
+    && source /opt/rh/devtoolset-${TOOLSET_VER}/enable \
     && export BOOST_INCLUDEDIR=/usr/include/boost169 \
     && export BOOST_LIBRARYDIR=/usr/lib64/boost169 \
     && cmake3 \
diff --git a/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_environment.h b/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_environment.h
index c60de87eb9..bf7ea6a61c 100644
--- a/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_environment.h
+++ b/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_environment.h
@@ -53,7 +53,7 @@ inline const std::string GetOtlpDefaultHttpEndpoint()
   return endpoint.size() ? endpoint : kOtlpEndpointDefault;
 }
 
-inline const bool GetOtlpDefaultIsSslEnable()
+inline bool GetOtlpDefaultIsSslEnable()
 {
   constexpr char kOtlpTracesIsSslEnableEnv[] = "OTEL_EXPORTER_OTLP_TRACES_SSL_ENABLE";
   constexpr char kOtlpIsSslEnableEnv[]       = "OTEL_EXPORTER_OTLP_SSL_ENABLE";
diff --git a/exporters/otlp/src/otlp_http_client.cc b/exporters/otlp/src/otlp_http_client.cc
index 544f74ca7c..e3e1a8c467 100644
--- a/exporters/otlp/src/otlp_http_client.cc
+++ b/exporters/otlp/src/otlp_http_client.cc
@@ -18,6 +18,7 @@
 #include "google/protobuf/message.h"
 #include "google/protobuf/reflection.h"
 #include "google/protobuf/stubs/common.h"
+#include "google/protobuf/stubs/stringpiece.h"
 #include "nlohmann/json.hpp"
 
 #if defined(GOOGLE_PROTOBUF_VERSION) && GOOGLE_PROTOBUF_VERSION >= 3007000