diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 16e5abaa7..2aa1f7478 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -1,106 +1,119 @@
-on:
+'on':
   push:
     branches:
-    - master
-  pull_request:
+      - 1.31.3-sp
+  pull_request: null
 name: ci
 jobs:
   units:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [7, 8, 11]
+        java:
+          - 7
+          - 8
+          - 11
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-java@v1
-      with:
-        java-version: ${{matrix.java}}
-    - run: java -version
-    - run: .kokoro/install_dependencies.sh
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: test
-    - name: coverage
-      uses: codecov/codecov-action@v1
-      with:
-        name: actions ${{matrix.java}}
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: ${{matrix.java}}
+      - run: java -version
+      - run: .kokoro/install_dependencies.sh
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: test
+      - name: coverage
+        uses: codecov/codecov-action@v1
+        with:
+          name: actions ${{matrix.java}}
   windows:
     runs-on: windows-latest
     steps:
-    - name: git configuration to avoid automatic CRLF conversion
-      run: |
-        git config --global core.autocrlf false
-        git config --global core.eol lf
-    - uses: actions/checkout@v2
-    - uses: actions/setup-java@v1
-      with:
-        java-version: 8
-    - run: java -version
-    - name: Install google-play-services artifact
-      shell: bash
-      run: |
-        mkdir play-services
-        cd play-services
-        curl --output play-services-basement-8.3.0.aar https://dl.google.com/dl/android/maven2/com/google/android/gms/play-services-basement/8.3.0/play-services-basement-8.3.0.aar
-        unzip play-services-basement-8.3.0.aar
-        mvn install:install-file \
-            -Dfile=classes.jar \
-            -DgroupId=com.google.android.google-play-services \
-            -DartifactId=google-play-services \
-            -Dversion=1 \
-            -Dpackaging=jar
-    - run: .kokoro/build.sh
-      shell: bash
-      env:
-        JOB_TYPE: test
+      - name: git configuration to avoid automatic CRLF conversion
+        run: |
+          git config --global core.autocrlf false
+          git config --global core.eol lf
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 8
+      - run: java -version
+      - name: Install google-play-services artifact
+        shell: bash
+        run: >
+          mkdir play-services
+
+          cd play-services
+
+          curl --output play-services-basement-8.3.0.aar
+          https://dl.google.com/dl/android/maven2/com/google/android/gms/play-services-basement/8.3.0/play-services-basement-8.3.0.aar
+
+          unzip play-services-basement-8.3.0.aar
+
+          mvn install:install-file \
+              -Dfile=classes.jar \
+              -DgroupId=com.google.android.google-play-services \
+              -DartifactId=google-play-services \
+              -Dversion=1 \
+              -Dpackaging=jar
+      - run: .kokoro/build.sh
+        shell: bash
+        env:
+          JOB_TYPE: test
   dependencies:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [8, 11]
+        java:
+          - 8
+          - 11
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-java@v1
-      with:
-        java-version: ${{matrix.java}}
-    - run: java -version
-    - run: .kokoro/install_dependencies.sh
-    - run: .kokoro/dependencies.sh
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: ${{matrix.java}}
+      - run: java -version
+      - run: .kokoro/install_dependencies.sh
+      - run: .kokoro/dependencies.sh
   linkage-monitor:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-java@v1
-      with:
-        java-version: 8
-    - run: java -version
-    - run: .kokoro/install_dependencies.sh
-    - name: Install artifacts to local Maven repository
-      run: .kokoro/build.sh
-      shell: bash
-    - name: Validate dependencies with regard to com.google.cloud:libraries-bom (latest release)
-      uses: GoogleCloudPlatform/cloud-opensource-java/linkage-monitor@v1-linkagemonitor
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 8
+      - run: java -version
+      - run: .kokoro/install_dependencies.sh
+      - name: Install artifacts to local Maven repository
+        run: .kokoro/build.sh
+        shell: bash
+      - name: >-
+          Validate dependencies with regard to com.google.cloud:libraries-bom
+          (latest release)
+        uses: >-
+          GoogleCloudPlatform/cloud-opensource-java/linkage-monitor@v1-linkagemonitor
   lint:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-java@v1
-      with:
-        java-version: 11
-    - run: java -version
-    - run: .kokoro/install_dependencies.sh
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: lint
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - run: java -version
+      - run: .kokoro/install_dependencies.sh
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: lint
   clirr:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-java@v1
-      with:
-        java-version: 8
-    - run: java -version
-    - run: .kokoro/install_dependencies.sh
-    - run: .kokoro/build.sh
-      env:
-        JOB_TYPE: clirr
\ No newline at end of file
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v1
+        with:
+          java-version: 8
+      - run: java -version
+      - run: .kokoro/install_dependencies.sh
+      - run: .kokoro/build.sh
+        env:
+          JOB_TYPE: clirr
diff --git a/google-api-client-protobuf/pom.xml b/google-api-client-protobuf/pom.xml
index c933af29e..441a4c1b1 100644
--- a/google-api-client-protobuf/pom.xml
+++ b/google-api-client-protobuf/pom.xml
@@ -77,9 +77,9 @@
         </executions>
       </plugin>
       <plugin>
-        <groupId>com.google.protobuf.tools</groupId>
-        <artifactId>maven-protoc-plugin</artifactId>
-        <version>0.4.2</version>
+        <groupId>org.xolstice.maven.plugins</groupId>
+        <artifactId>protobuf-maven-plugin</artifactId>
+        <version>0.6.1</version>
         <configuration>
           <protocArtifact>com.google.protobuf:protoc:${project.protobuf-java.version}:exe:${os.detected.classifier}</protocArtifact>
         </configuration>
diff --git a/google-api-client/pom.xml b/google-api-client/pom.xml
index 1beafce52..5836bba64 100644
--- a/google-api-client/pom.xml
+++ b/google-api-client/pom.xml
@@ -90,9 +90,9 @@
         </executions>
       </plugin>
       <plugin>
-        <groupId>com.google.protobuf.tools</groupId>
-        <artifactId>maven-protoc-plugin</artifactId>
-        <version>0.4.2</version>
+        <groupId>org.xolstice.maven.plugins</groupId>
+        <artifactId>protobuf-maven-plugin</artifactId>
+        <version>0.6.1</version>
         <configuration>
           <protocArtifact>com.google.protobuf:protoc:${project.protobuf-java.version}:exe:${os.detected.classifier}</protocArtifact>
         </configuration>
diff --git a/pom.xml b/pom.xml
index 2c80fa596..dda9f9621 100644
--- a/pom.xml
+++ b/pom.xml
@@ -78,10 +78,6 @@
       <name>Central Repository</name>
       <url>https://repo.maven.apache.org/maven2</url>
     </pluginRepository>
-    <pluginRepository>
-      <id>protoc-plugin</id>
-      <url>https://dl.bintray.com/sergei-ivanov/maven/</url>
-    </pluginRepository>
   </pluginRepositories>
 
   <dependencyManagement>