diff --git a/basyx.aasxfileserver/basyx.aasxfileserver-backend/src/main/java/org/eclipse/digitaltwin/basyx/aasxfileserver/backend/CrudAASXFileServer.java b/basyx.aasxfileserver/basyx.aasxfileserver-backend/src/main/java/org/eclipse/digitaltwin/basyx/aasxfileserver/backend/CrudAASXFileServer.java
index 859da0d3e..8646db52f 100644
--- a/basyx.aasxfileserver/basyx.aasxfileserver-backend/src/main/java/org/eclipse/digitaltwin/basyx/aasxfileserver/backend/CrudAASXFileServer.java
+++ b/basyx.aasxfileserver/basyx.aasxfileserver-backend/src/main/java/org/eclipse/digitaltwin/basyx/aasxfileserver/backend/CrudAASXFileServer.java
@@ -156,7 +156,7 @@ private String fullyDeletePackage(Package pkg) {
 	}
 
 	private boolean containsShellId(PackageDescription packageDesc, String shellId) {
-		return packageDesc.getItems().stream().anyMatch(aasId -> aasId.equals(shellId));
+		return packageDesc.getAasIds().stream().anyMatch(aasId -> aasId.equals(shellId));
 	}
 
 	private Stream<Package> getPackages() {
@@ -167,7 +167,7 @@ private Stream<Package> getPackages() {
 	private static PackageDescription createPackageDescription(List<String> shellIds, String newPackageId) {
 		PackageDescription packageDescription = new DefaultPackageDescription();
 		packageDescription.setPackageId(newPackageId);
-		packageDescription.setItems(shellIds);
+		packageDescription.setAasIds(shellIds);
 
 		return packageDescription;
 	}
diff --git a/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/AASXFileServerSuite.java b/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/AASXFileServerSuite.java
index 6830a380f..cd854af75 100644
--- a/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/AASXFileServerSuite.java
+++ b/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/AASXFileServerSuite.java
@@ -123,7 +123,7 @@ public void updateExistingAASXByPackageId() throws IOException {
 
 		PackageDescription expectedPackageDescription = new DefaultPackageDescription();
 		expectedPackageDescription.setPackageId(initialPackageDescription.getPackageId());
-		expectedPackageDescription.setItems(DummyAASXFileServerFactory.SECOND_SHELL_IDS);
+		expectedPackageDescription.setAasIds(DummyAASXFileServerFactory.SECOND_SHELL_IDS);
 
 		CursorResult<List<PackageDescription>> pagedPackageDescriptions = server.getAllAASXPackageIds("", PaginationInfo.NO_LIMIT);
 		List<PackageDescription> actualPackageDescription = pagedPackageDescriptions.getResult();
diff --git a/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/DummyAASXFileServerFactory.java b/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/DummyAASXFileServerFactory.java
index 91dfb55e5..4ee5a390f 100644
--- a/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/DummyAASXFileServerFactory.java
+++ b/basyx.aasxfileserver/basyx.aasxfileserver-core/src/test/java/org/eclipse/digitaltwin/basyx/aasxfileserver/core/DummyAASXFileServerFactory.java
@@ -78,7 +78,7 @@ public static List<PackageDescription> createMultipleDummyAASXPackagesOnServer(A
 	public static PackageDescription createDummyPackageDescription(String packageId, List<String> shellIds) {
 		PackageDescription expectedDescription1 = new DefaultPackageDescription();
 		expectedDescription1.setPackageId(packageId);
-		expectedDescription1.setItems(shellIds);
+		expectedDescription1.setAasIds(shellIds);
 
 		return expectedDescription1;
 	}
diff --git a/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/DummySubmodelFactory.java b/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/DummySubmodelFactory.java
index a6086000d..2b502441e 100644
--- a/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/DummySubmodelFactory.java
+++ b/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/DummySubmodelFactory.java
@@ -195,14 +195,13 @@ private static List<SubmodelElement> getOperationalDataSubmodelElements() {
 	}
 
 	private static List<SubmodelElement> createOperationalDataSubmodelElements() {
-		ArrayList<SubmodelElement> list = new ArrayList<>();
-
+		List<SubmodelElement> list = new ArrayList<>();
 		SubmodelElement sme1 = createProperty(SUBMODEL_OPERATIONAL_DATA_PROPERTY_ID_SHORT);
 		SubmodelElement sme2 = createProperty(SUBMODEL_ELEMENT_FIRST_ID_SHORT);
 		SubmodelElement sme3 = createProperty(SUBMODEL_ELEMENT_SECOND_ID_SHORT);
 
 		SubmodelElementCollection submodelElementCollection = new DefaultSubmodelElementCollection();
-		SubmodelElementList submodelElementList = new DefaultSubmodelElementList();
+		SubmodelElementList submodelElementList = new DefaultSubmodelElementList.Builder().orderRelevant(true).build();
 
 		List<SubmodelElement> submodelElementsCollection = new ArrayList<>();
 		List<SubmodelElement> submodelElementsList = new ArrayList<>();
@@ -231,8 +230,8 @@ private static void setValuesOfSubmodelElements(SubmodelElement sme2, SubmodelEl
 
 	private static SubmodelElementCollection createNestedElementCollection(SubmodelElement sme2) {
 		SubmodelElementCollection topLevelElementCollection = new DefaultSubmodelElementCollection();
-		SubmodelElementList submodelElementListInElementCollection = new DefaultSubmodelElementList();
-		SubmodelElementList submodelElementListInElementList = new DefaultSubmodelElementList();
+		SubmodelElementList submodelElementListInElementCollection = new DefaultSubmodelElementList.Builder().orderRelevant(true).build();
+		SubmodelElementList submodelElementListInElementList = new DefaultSubmodelElementList.Builder().orderRelevant(true).build();
 		SubmodelElementCollection submodelElementCollectionInElementList = new DefaultSubmodelElementCollection();
 		List<SubmodelElement> submodelElementCollectionInElementListCollection = new ArrayList<>();
 		List<SubmodelElement> listForSubmodelElementListInElementList = new ArrayList<>();
@@ -272,7 +271,7 @@ private static List<SubmodelElement> createSimpleSubmodelElements() {
 		smeCollection.setIdShort(SUBMODEL_ELEMENT_COLLECTION_SIMPLE);
 		smeCollectionValue.add(createProperty(SUBMODEL_ELEMENT_FIRST_ID_SHORT));
 
-		SubmodelElementList smeList = new DefaultSubmodelElementList();
+		SubmodelElementList smeList = new DefaultSubmodelElementList.Builder().orderRelevant(true).build();
 		smeList.setIdShort(SUBMODEL_ELEMENT_LIST_SIMPLE);
 		smeListValue.add(createProperty(SUBMODEL_ELEMENT_SECOND_ID_SHORT));
 
diff --git a/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceHelper.java b/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceHelper.java
index 7fe1161e4..ca35b5565 100644
--- a/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceHelper.java
+++ b/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceHelper.java
@@ -324,6 +324,7 @@ public static SubmodelElementList createSubmodelElementList() {
 				.build())
 				.idShort(SUBMODEL_TECHNICAL_DATA_SUBMODEL_ELEMENT_LIST_ID_SHORT)
 				.category(SUBMODEL_TECHNICAL_DATA_SUBMODEL_ELEMENT_LIST_CATEGORY)
+				.orderRelevant(true)
 				.value(Lists.newArrayList(createRangeSubmodelElement(), createPropertySubmodelElement()))
 				.build();
 	}
diff --git a/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceSuite.java b/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceSuite.java
index b00132378..e8b4687c6 100644
--- a/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceSuite.java
+++ b/basyx.submodelservice/basyx.submodelservice-core/src/test/java/org/eclipse/digitaltwin/basyx/submodelservice/SubmodelServiceSuite.java
@@ -146,7 +146,7 @@ public void getHierarchicalSubmodelElementWhenFirstElementIsList() {
 
 		List<SubmodelElement> submodelElementsList = new ArrayList<>();
 
-		SubmodelElementList submodelElementList = new DefaultSubmodelElementList();
+		SubmodelElementList submodelElementList = new DefaultSubmodelElementList.Builder().orderRelevant(true).build();
 		submodelElementList.setIdShort("testList");
 		List<SubmodelElement> listElements = new ArrayList<>();
 		Property testProperty = new DefaultProperty.Builder().idShort("propIdShort").category("cat1").value("123").valueType(DataTypeDefXsd.INTEGER).build();
@@ -734,7 +734,7 @@ private String generateNestedIdShortPath() {
 	}
 
 	private DefaultSubmodelElementList createDummySubmodelElementList(String idShort) {
-		return new DefaultSubmodelElementList.Builder().idShort(idShort).build();
+		return new DefaultSubmodelElementList.Builder().idShort(idShort).orderRelevant(true).build();
 	}
 
 	private SubmodelElementCollection createDummySubmodelElementCollection(String idShort) {
diff --git a/pom.xml b/pom.xml
index d288b9634..3b76ea3d2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -67,7 +67,7 @@
 		<docker.target.platforms>linux/amd64, linux/arm64, linux/arm/v7</docker.target.platforms>
 		<docker.host.port>8081</docker.host.port>
 		<docker.container.port>8081</docker.container.port>
-		<aas4j-version>1.0.5</aas4j-version>
+		<aas4j-version>2.0.0</aas4j-version>
 		<querydsl-version>5.1.0</querydsl-version>
 		<jakarta-version>3.2.0</jakarta-version>
 	</properties>
@@ -82,7 +82,7 @@
 			</snapshots>
 		</pluginRepository>
 	</pluginRepositories>
-
+	
 	<build>
 		<plugins>
 			<plugin>