diff --git a/lombok.config b/lombok.config
index 81661f0fd9c5f6e2f40f39aa9ee13f7017fc2726..a0e918012b6da2b2cd06374cf7ac35d085bfa3e0 100644
--- a/lombok.config
+++ b/lombok.config
@@ -27,4 +27,5 @@ lombok.log.slf4j.flagUsage = ERROR
 lombok.log.log4j.flagUsage = ERROR
 lombok.data.flagUsage = ERROR
 lombok.nonNull.exceptionType = IllegalArgumentException
-lombok.addLombokGeneratedAnnotation = true
\ No newline at end of file
+lombok.addLombokGeneratedAnnotation = true
+lombok.copyableAnnotations += org.springframework.beans.factory.annotation.Qualifier
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index 16fb006bed5bd4a396d98a75422044f43c1b3f19..61a64720dc3408155c9eb38f63d9f84f4d155066 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1,6 +1,8 @@
 <!--
-  ~ Copyright (c) 2024.  Das Land Schleswig-Holstein vertreten durch den Ministerpräsidenten des Landes
-  ~ Schleswig-Holstein Staatskanzlei Abteilung Digitalisierung und zentrales IT-Management der Landesregierung
+  ~ Copyright (c) 2024.  Das Land Schleswig-Holstein vertreten durch den Ministerpräsidenten des
+Landes
+  ~ Schleswig-Holstein Staatskanzlei Abteilung Digitalisierung und zentrales IT-Management der
+Landesregierung
   ~
   ~ Lizenziert unter der EUPL, Version 1.2 oder - sobald
   ~ diese von der Europäischen Kommission genehmigt wurden -
@@ -21,14 +23,14 @@
   -->
 
 <project xmlns="http://maven.apache.org/POM/4.0.0"
-		 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 
 	<parent>
 		<groupId>de.ozgcloud.common</groupId>
 		<artifactId>ozgcloud-common-parent</artifactId>
-		<version>4.0.1</version>
+		<version>4.3.2</version>
 	</parent>
 
 	<groupId>de.ozgcloud.muk</groupId>
@@ -39,7 +41,7 @@
 	<description>OZG-Cloud MUK Postfach</description>
 
 	<properties>
-		<api-lib.version>0.9.0</api-lib.version>
+		<api-lib.version>0.12.0</api-lib.version>
 		<nachrichten-manager.version>2.10.0-SNAPSHOT</nachrichten-manager.version>
 		<jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
 		<wiremock.version>3.5.4</wiremock.version>
@@ -153,7 +155,8 @@
 							<goal>generate</goal>
 						</goals>
 						<configuration>
-							<inputSpec>${project.basedir}/src/main/resources/${elster-transfer.version}
+							<inputSpec>
+								${project.basedir}/src/main/resources/${elster-transfer.version}
 							</inputSpec>
 							<generatorName>java</generatorName>
 							<generateApis>false</generateApis>
@@ -181,4 +184,4 @@
 			</plugin>
 		</plugins>
 	</build>
-</project>
+</project>
\ No newline at end of file
diff --git a/src/main/java/de/ozgcloud/nachrichten/postfach/muk/MukPostfachCallContextProvider.java b/src/main/java/de/ozgcloud/nachrichten/postfach/muk/MukPostfachCallContextProvider.java
new file mode 100644
index 0000000000000000000000000000000000000000..b65237d4770a75b65c9b9553a11f4589318c8560
--- /dev/null
+++ b/src/main/java/de/ozgcloud/nachrichten/postfach/muk/MukPostfachCallContextProvider.java
@@ -0,0 +1,17 @@
+package de.ozgcloud.nachrichten.postfach.muk;
+
+import org.springframework.stereotype.Component;
+
+import de.ozgcloud.apilib.common.callcontext.CallContext;
+import de.ozgcloud.apilib.common.callcontext.OzgCloudCallContextProvider;
+import lombok.RequiredArgsConstructor;
+
+@Component
+@RequiredArgsConstructor
+class MukPostfachCallContextProvider implements OzgCloudCallContextProvider {
+
+	@Override
+	public CallContext provideContext() {
+		return CallContext.builder().clientName(MukPostfachConfiguration.MUK_POSTFACH_CLIENT_NAME).build();
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/de/ozgcloud/nachrichten/postfach/muk/MukPostfachConfiguration.java b/src/main/java/de/ozgcloud/nachrichten/postfach/muk/MukPostfachConfiguration.java
new file mode 100644
index 0000000000000000000000000000000000000000..bfec782bac5ddadb10a12ab64289eb636b4933de
--- /dev/null
+++ b/src/main/java/de/ozgcloud/nachrichten/postfach/muk/MukPostfachConfiguration.java
@@ -0,0 +1,31 @@
+package de.ozgcloud.nachrichten.postfach.muk;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import de.ozgcloud.apilib.file.OzgCloudFileService;
+import de.ozgcloud.apilib.file.grpc.GrpcOzgCloudFileService;
+import de.ozgcloud.apilib.file.grpc.OzgCloudFileMapper;
+import de.ozgcloud.vorgang.grpc.binaryFile.BinaryFileServiceGrpc.BinaryFileServiceBlockingStub;
+import de.ozgcloud.vorgang.grpc.binaryFile.BinaryFileServiceGrpc.BinaryFileServiceStub;
+import net.devh.boot.grpc.client.inject.GrpcClient;
+
+@Configuration
+public class MukPostfachConfiguration {
+
+	public static final String OZG_CLOUD_FILE_SERVICE_NAME = "mukPostfach_OzgCloudFileService";
+
+	public static final String GRPC_FILE_MANAGER_NAME = "file-manager";
+
+	public static final String MUK_POSTFACH_CLIENT_NAME = "OzgCloud_MukPostfach";
+
+	@GrpcClient(GRPC_FILE_MANAGER_NAME)
+	private BinaryFileServiceBlockingStub fileServiceBlockingStub;
+	@GrpcClient(GRPC_FILE_MANAGER_NAME)
+	private BinaryFileServiceStub fileServiceAsyncServiceStub;
+
+	@Bean(OZG_CLOUD_FILE_SERVICE_NAME) // NOSONAR
+	OzgCloudFileService grpcOzgCloudFileService(MukPostfachCallContextProvider contextProvider, OzgCloudFileMapper mapper) {
+		return new GrpcOzgCloudFileService(fileServiceBlockingStub, fileServiceAsyncServiceStub, contextProvider, mapper);
+	}
+}
diff --git a/src/main/java/de/ozgcloud/nachrichten/postfach/muk/transfer/AttachmentService.java b/src/main/java/de/ozgcloud/nachrichten/postfach/muk/transfer/AttachmentService.java
index 5a259d19982ae9ed73df9280e9c76b1bca7cbc6e..09b376460edf735193f39cb3d84f4ddfb4891589 100644
--- a/src/main/java/de/ozgcloud/nachrichten/postfach/muk/transfer/AttachmentService.java
+++ b/src/main/java/de/ozgcloud/nachrichten/postfach/muk/transfer/AttachmentService.java
@@ -25,19 +25,20 @@ package de.ozgcloud.nachrichten.postfach.muk.transfer;
 import java.io.BufferedInputStream;
 import java.io.OutputStream;
 
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Service;
 
 import de.ozgcloud.apilib.file.OzgCloudFile;
 import de.ozgcloud.apilib.file.OzgCloudFileId;
 import de.ozgcloud.apilib.file.OzgCloudFileService;
 import de.ozgcloud.apilib.file.OzgCloudUploadFile;
+import de.ozgcloud.nachrichten.postfach.muk.MukPostfachConfiguration;
 import lombok.RequiredArgsConstructor;
-import lombok.extern.log4j.Log4j2;
 
-@Log4j2
 @Service
 @RequiredArgsConstructor
 public class AttachmentService {
+	@Qualifier(MukPostfachConfiguration.OZG_CLOUD_FILE_SERVICE_NAME) // NOSONAR
 	private final OzgCloudFileService ozgCloudFileService;
 
 	OzgCloudFile getCloudFile(String fileId) {