diff --git a/.config/checkstyle/checkstyle.xml b/.config/checkstyle/checkstyle.xml
index b5a41357..463a629a 100644
--- a/.config/checkstyle/checkstyle.xml
+++ b/.config/checkstyle/checkstyle.xml
@@ -74,6 +74,11 @@
 			<!-- https://docs.pmd-code.org/pmd-doc-7.11.0/pmd_rules_java_errorprone.html#avoidcatchingthrowable -->
 			<property name="illegalClassNames" value="Error,Throwable,NullPointerException,java.lang.Error,java.lang.Throwable,java.lang.NullPointerException"/>
 		</module>
+		<!-- Do not allow params and vars to end with collection type names -->
+		<module name="IllegalIdentifierName">
+			<property name="format" value="^(?!(.*(Map|List|Set))$).+$"/>
+			<property name="tokens" value="PARAMETER_DEF, VARIABLE_DEF, PATTERN_VARIABLE_DEF, RECORD_COMPONENT_DEF, LAMBDA"/>
+		</module>
 		<module name="IllegalImport"/>
 		<module name="InterfaceIsType"/>
 		<module name="JavadocStyle">
@@ -122,7 +127,10 @@
 		<module name="StaticVariableName"/>
 		<module name="StringLiteralEquality"/>
 		<module name="SuppressWarningsHolder"/>
-		<module name="TodoComment"/>
+		<module name="TodoComment">
+			<!-- Default is "TODO:" -->
+			<property name="format" value="(?i)(TODO)"/>
+		</module>
 		<module name="TypecastParenPad"/>
 		<module name="TypeName"/>
 		<module name="UnnecessaryParentheses"/>
diff --git a/.config/pmd/java/ruleset.xml b/.config/pmd/java/ruleset.xml
index c057d1aa..e96576b1 100644
--- a/.config/pmd/java/ruleset.xml
+++ b/.config/pmd/java/ruleset.xml
@@ -394,6 +394,30 @@ If you are 100% sure that you escaped the value properly and you have no better
 		</properties>
 	</rule>
 
+	<!-- Jakarta Persistence -->
+	<rule name="AvoidListAsEntityRelation"
+		language="java"
+		message="Use a Set instead of a List in entity relations"
+		class="net.sourceforge.pmd.lang.rule.xpath.XPathRule"
+		externalInfoUrl="https://www.baeldung.com/spring-jpa-onetomany-list-vs-set#bd-pros-and-cons">
+		<description>
+`List` allows duplicates while a `Set` does not.
+A `Set` also prevents duplicates when the ORM reads multiple identical rows from the database (e.g. when using JOIN).
+		</description>
+		<priority>2</priority>
+		<properties>
+			<property name="xpath">
+				<value>
+<![CDATA[
+//ClassDeclaration[pmd-java:hasAnnotation('jakarta.persistence.Entity')]
+//FieldDeclaration[pmd-java:hasAnnotation('jakarta.persistence.ManyToMany') or pmd-java:hasAnnotation('jakarta.persistence.OneToMany')]
+/ClassType[pmd-java:typeIs('java.util.List')]
+]]>
+				</value>
+			</property>
+		</properties>
+	</rule>
+
 
 	<!-- Rules from JPinPoint with slight modifications -->
 	<!-- https://github.com/jborgers/PMD-jPinpoint-rules -->
diff --git a/.github/workflows/check-build.yml b/.github/workflows/check-build.yml
index 38497bb1..b1a6d66f 100644
--- a/.github/workflows/check-build.yml
+++ b/.github/workflows/check-build.yml
@@ -40,7 +40,7 @@ jobs:
         java-version: ${{ matrix.java }}
 
     - name: Cache Maven
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-mvn-build-${{ hashFiles('**/pom.xml') }}
@@ -69,7 +69,7 @@ jobs:
         fi
 
     - name: Upload demo files
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       with:
         name: demo-files-java-${{ matrix.java }}
         path: ${{ env.DEMO_MAVEN_MODULE }}/target/${{ env.DEMO_MAVEN_MODULE }}.jar
@@ -81,7 +81,7 @@ jobs:
     timeout-minutes: 15
     strategy:
       matrix:
-        java: [17]
+        java: [21]
         distribution: [temurin]
     steps:
     - uses: actions/checkout@v6
@@ -93,7 +93,7 @@ jobs:
         java-version: ${{ matrix.java }}
 
     - name: Cache Maven
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-mvn-checkstyle-${{ hashFiles('**/pom.xml') }}
@@ -101,7 +101,7 @@ jobs:
           ${{ runner.os }}-mvn-checkstyle-
 
     - name: CheckStyle Cache
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: '**/target/checkstyle-cachefile'
         key: ${{ runner.os }}-checkstyle-${{ hashFiles('**/pom.xml') }}
@@ -129,7 +129,7 @@ jobs:
         java-version: ${{ matrix.java }}
 
     - name: Cache Maven
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-mvn-pmd-${{ hashFiles('**/pom.xml') }}
@@ -137,7 +137,7 @@ jobs:
           ${{ runner.os }}-mvn-pmd-
 
     - name: PMD Cache
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: '**/target/pmd/pmd.cache'
         key: ${{ runner.os }}-pmd-${{ hashFiles('**/pom.xml') }}
@@ -152,7 +152,7 @@ jobs:
 
     - name: Upload report
       if: always()
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       with:
         name: pmd-report
         if-no-files-found: ignore
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index e0265f26..3f55399a 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -28,7 +28,7 @@ jobs:
 
     # Try to reuse existing cache from check-build
     - name: Try restore Maven Cache
-      uses: actions/cache/restore@v4
+      uses: actions/cache/restore@v5
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-mvn-build-${{ hashFiles('**/pom.xml') }}
@@ -91,7 +91,7 @@ jobs:
 
     - name: Create Release
       id: create-release
-      uses: shogo82148/actions-create-release@28d99e2a5b407558d17c15d0384fc0d7fb625b4c # v1
+      uses: shogo82148/actions-create-release@559c27ce7eb834825e2b55927c64f6d1bd1db716 # v1
       with:
         tag_name: v${{ steps.version.outputs.release }}
         release_name: v${{ steps.version.outputs.release }}
@@ -179,7 +179,7 @@ jobs:
 
     # Try to reuse existing cache from check-build
     - name: Try restore Maven Cache
-      uses: actions/cache/restore@v4
+      uses: actions/cache/restore@v5
       with:
         path: ~/.m2/repository
         key: ${{ runner.os }}-mvn-build-${{ hashFiles('**/pom.xml') }}
diff --git a/.idea/checkstyle-idea.xml b/.idea/checkstyle-idea.xml
index ec555b58..a751c417 100644
--- a/.idea/checkstyle-idea.xml
+++ b/.idea/checkstyle-idea.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="CheckStyle-IDEA" serialisationVersion="2">
-    <checkstyleVersion>11.0.0</checkstyleVersion>
+    <checkstyleVersion>13.0.0</checkstyleVersion>
     <scanScope>JavaOnlyWithTests</scanScope>
     <suppressErrors>true</suppressErrors>
     <copyLibs>true</copyLibs>
diff --git a/.mvn/wrapper/maven-wrapper.properties b/.mvn/wrapper/maven-wrapper.properties
index c0bcafe9..8dea6c22 100644
--- a/.mvn/wrapper/maven-wrapper.properties
+++ b/.mvn/wrapper/maven-wrapper.properties
@@ -1,3 +1,3 @@
 wrapperVersion=3.3.4
 distributionType=only-script
-distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.11/apache-maven-3.9.11-bin.zip
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.12/apache-maven-3.9.12-bin.zip
diff --git a/pom.xml b/pom.xml
index 4ddf0d83..84ce434e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -45,7 +45,7 @@
 							<dependency>
 								<groupId>com.puppycrawl.tools</groupId>
 								<artifactId>checkstyle</artifactId>
-								<version>12.2.0</version>
+								<version>13.0.0</version>
 							</dependency>
 						</dependencies>
 						<configuration>
@@ -83,12 +83,12 @@
 							<dependency>
 								<groupId>net.sourceforge.pmd</groupId>
 								<artifactId>pmd-core</artifactId>
-								<version>7.19.0</version>
+								<version>7.20.0</version>
 							</dependency>
 							<dependency>
 								<groupId>net.sourceforge.pmd</groupId>
 								<artifactId>pmd-java</artifactId>
-								<version>7.19.0</version>
+								<version>7.20.0</version>
 							</dependency>
 						</dependencies>
 					</plugin>
diff --git a/template-placeholder/pom.xml b/template-placeholder/pom.xml
index 57263e36..3738a65c 100644
--- a/template-placeholder/pom.xml
+++ b/template-placeholder/pom.xml
@@ -193,7 +193,7 @@
 					<plugin>
 						<groupId>org.sonatype.central</groupId>
 						<artifactId>central-publishing-maven-plugin</artifactId>
-						<version>0.9.0</version>
+						<version>0.10.0</version>
 						<extensions>true</extensions>
 						<configuration>
 							<publishingServerId>sonatype-central-portal</publishingServerId>
@@ -215,7 +215,7 @@
 							<dependency>
 								<groupId>com.puppycrawl.tools</groupId>
 								<artifactId>checkstyle</artifactId>
-								<version>12.2.0</version>
+								<version>13.0.0</version>
 							</dependency>
 						</dependencies>
 						<configuration>
@@ -253,12 +253,12 @@
 							<dependency>
 								<groupId>net.sourceforge.pmd</groupId>
 								<artifactId>pmd-core</artifactId>
-								<version>7.19.0</version>
+								<version>7.20.0</version>
 							</dependency>
 							<dependency>
 								<groupId>net.sourceforge.pmd</groupId>
 								<artifactId>pmd-java</artifactId>
-								<version>7.19.0</version>
+								<version>7.20.0</version>
 							</dependency>
 						</dependencies>
 					</plugin>