diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5e88435..5543c82 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,11 +3,25 @@ name: CI
 on: [push]
 
 jobs:
+
   build:
+
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # The MODULE environment variable is evaluated in build-all.sh to run a subset
+        # of the builds. This way, multiple modules can be built in parallel.
+        module:
+          - module1
+          - module2
+          - module3
+          - module4
+
     steps:
+
     - name: "Checkout sources"
       uses: actions/checkout@v1
+
     - name: "Setup Java"
       uses: actions/setup-java@v1
       env:
@@ -18,5 +32,9 @@ jobs:
         AWS_REGION: ${{ secrets.AWSREGION }}
       with:
         java-version: 13
-    - name: "Build all modules"
-      run: chmod 755 build-all.sh && ./build-all.sh
+
+    - name: "Build module ${{ matrix.module }}"
+      with:
+        MODULE: ${{ matrix.module }}
+      run: |
+        chmod 755 build-all.sh && ./build-all.sh
diff --git a/build-all.sh b/build-all.sh
index 4b5a9c5..9695d0c 100755
--- a/build-all.sh
+++ b/build-all.sh
@@ -81,58 +81,85 @@ build_maven_module() {
   }
 }
 
-build_maven_module "spring-boot/spring-boot-kafka"
-build_maven_module "resilience4j/retry"
-build_maven_module "solid/lsp"
-run_gradle_task "spring-boot/thymeleaf-vue" "npmInstall"
-build_gradle_module "spring-boot/thymeleaf-vue"
-build_gradle_module "spring-boot/spring-boot-springdoc"
-build_maven_module "spring-boot/dependency-injection"
-build_maven_module "spring-boot/spring-boot-openapi"
-build_maven_module "spring-boot/data-migration/liquibase"
-build_gradle_module "spring-boot/boundaries"
-build_gradle_module "spring-boot/argumentresolver"
-build_gradle_module "spring-data/spring-data-jdbc-converter"
-build_gradle_module "solid"
-build_gradle_module "spring-boot/data-migration/flyway"
-build_gradle_module "reactive"
-build_gradle_module "junit/assumptions"
-build_gradle_module "logging"
-build_gradle_module "pact/pact-feign-consumer"
-# currently disabled since the consumer build won't run
-# build_gradle_module "pact/pact-message-consumer"
-# build_gradle_module "pact/pact-message-producer"
-build_gradle_module "pact/pact-spring-provider"
-build_gradle_module "patterns"
-build_gradle_module "spring-boot/conditionals"
-build_gradle_module "spring-boot/configuration"
-build_gradle_module "spring-boot/mocking"
-build_gradle_module "spring-boot/modular"
-build_gradle_module "spring-boot/paging"
-build_gradle_module "spring-boot/rabbitmq-event-brokering"
-build_gradle_module "spring-boot/spring-boot-logging"
-build_gradle_module "spring-boot/spring-boot-testing"
-build_gradle_module "spring-boot/starter"
-build_gradle_module "spring-boot/startup"
-build_gradle_module "spring-boot/static"
-build_gradle_module "spring-boot/validation"
-build_gradle_module "spring-boot/profiles"
-build_gradle_module "spring-boot/password-encoding"
-build_gradle_module "spring-boot/testcontainers"
-build_gradle_module "spring-boot/hazelcast/hazelcast-embedded-cache"
-build_gradle_module "spring-boot/hazelcast/hazelcast-client-server"
-build_gradle_module "spring-boot/cache"
-build_gradle_module "spring-cloud/feign-with-spring-data-rest"
-build_gradle_module "spring-cloud/sleuth-downstream-service"
-build_gradle_module "spring-cloud/sleuth-upstream-service"
-build_gradle_module "spring-cloud/spring-cloud-contract-consumer"
-build_gradle_module "spring-cloud/spring-cloud-contract-provider"
-build_gradle_module "spring-data/spring-data-rest-associations"
-build_gradle_module "spring-data/spring-data-rest-springfox"
-build_gradle_module "tools/jacoco"
-build_maven_module "aws/localstack"
+if [[ "$MODULE" == "module1" ]]
+then
+  build_maven_module "spring-boot/spring-boot-kafka"
+  build_gradle_module "spring-boot/thymeleaf-vue"
+  build_gradle_module "spring-boot/spring-boot-springdoc"
+  build_maven_module "spring-boot/dependency-injection"
+  build_maven_module "spring-boot/spring-boot-openapi"
+  build_maven_module "spring-boot/data-migration/liquibase"
+  build_gradle_module "spring-boot/boundaries"
+  build_gradle_module "spring-boot/argumentresolver"
+  build_gradle_module "spring-boot/data-migration/flyway"
+  run_gradle_task "spring-boot/thymeleaf-vue" "npmInstall"
+  build_gradle_module "spring-boot/conditionals"
+  build_gradle_module "spring-boot/configuration"
 
-echo ""
-echo "+++"
-echo "+++ ALL MODULES SUCCESSFUL"
-echo "+++"
+  echo ""
+  echo "+++"
+  echo "+++ MODULE 1 SUCCESSFUL"
+  echo "+++"
+fi
+
+if [[ "$MODULE" == "module2" ]]
+then
+  build_maven_module "resilience4j/retry"
+  build_maven_module "solid/lsp"
+  build_gradle_module "spring-data/spring-data-jdbc-converter"
+  build_gradle_module "solid"
+  build_gradle_module "reactive"
+  build_gradle_module "junit/assumptions"
+  build_gradle_module "logging"
+  build_gradle_module "pact/pact-feign-consumer"
+
+  echo ""
+  echo "+++"
+  echo "+++ MODULE 2 SUCCESSFUL"
+  echo "+++"
+fi
+
+if [[ "$MODULE" == "module3" ]]
+then
+  build_gradle_module "pact/pact-spring-provider"
+  build_gradle_module "patterns"
+  build_gradle_module "spring-cloud/feign-with-spring-data-rest"
+  build_gradle_module "spring-cloud/sleuth-downstream-service"
+  build_gradle_module "spring-cloud/sleuth-upstream-service"
+  build_gradle_module "spring-cloud/spring-cloud-contract-consumer"
+  build_gradle_module "spring-cloud/spring-cloud-contract-provider"
+  build_gradle_module "spring-data/spring-data-rest-associations"
+  build_gradle_module "spring-data/spring-data-rest-springfox"
+  build_gradle_module "tools/jacoco"
+  build_maven_module "aws/localstack"
+
+  echo ""
+  echo "+++"
+  echo "+++ MODULE 3 SUCCESSFUL"
+  echo "+++"
+fi
+
+if [[ "$MODULE" == "module4" ]]
+then
+  build_gradle_module "spring-boot/mocking"
+  build_gradle_module "spring-boot/modular"
+  build_gradle_module "spring-boot/paging"
+  build_gradle_module "spring-boot/rabbitmq-event-brokering"
+  build_gradle_module "spring-boot/spring-boot-logging"
+  build_gradle_module "spring-boot/spring-boot-testing"
+  build_gradle_module "spring-boot/starter"
+  build_gradle_module "spring-boot/startup"
+  build_gradle_module "spring-boot/static"
+  build_gradle_module "spring-boot/validation"
+  build_gradle_module "spring-boot/profiles"
+  build_gradle_module "spring-boot/password-encoding"
+  build_gradle_module "spring-boot/testcontainers"
+  build_gradle_module "spring-boot/hazelcast/hazelcast-embedded-cache"
+  build_gradle_module "spring-boot/hazelcast/hazelcast-client-server"
+  build_gradle_module "spring-boot/cache"
+
+  echo ""
+  echo "+++"
+  echo "+++ MODULE 4 SUCCESSFUL"
+  echo "+++"
+fi
\ No newline at end of file
diff --git a/patterns/gradlew b/patterns/gradlew
old mode 100644
new mode 100755
diff --git a/spring-boot/starter/application/build.gradle b/spring-boot/starter/application/build.gradle
index 8487066..9d8539d 100644
--- a/spring-boot/starter/application/build.gradle
+++ b/spring-boot/starter/application/build.gradle
@@ -6,7 +6,7 @@ plugins {
 
 group = 'io.reflectoring'
 version = '0.0.1-SNAPSHOT'
-sourceCompatibility = '13'
+sourceCompatibility = '11'
 
 repositories {
 	mavenCentral()
diff --git a/spring-boot/starter/event-starter/build.gradle b/spring-boot/starter/event-starter/build.gradle
index d4f5833..a90e4cc 100644
--- a/spring-boot/starter/event-starter/build.gradle
+++ b/spring-boot/starter/event-starter/build.gradle
@@ -5,7 +5,7 @@ plugins {
 
 group = 'io.reflectoring'
 version = '0.0.1-SNAPSHOT'
-sourceCompatibility = '13'
+sourceCompatibility = '11'
 
 repositories {
     mavenCentral()