diff --git a/.idea/kotlinc.xml b/.idea/kotlinc.xml
index f8467b4..e805548 100644
--- a/.idea/kotlinc.xml
+++ b/.idea/kotlinc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="KotlinJpsPluginSettings">
-    <option name="version" value="1.9.10" />
+    <option name="version" value="1.9.20" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
index e22a80c..22c47fb 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -7,6 +7,7 @@
       <module fileurl="file://$PROJECT_DIR$/.idea/modules/mps/metamodel/modelix-samples.mps.metamodel.main.iml" filepath="$PROJECT_DIR$/.idea/modules/mps/metamodel/modelix-samples.mps.metamodel.main.iml" />
       <module fileurl="file://$PROJECT_DIR$/.idea/modules/mps/project-modelserver-backend/modelix-samples.mps.project-modelserver-backend.iml" filepath="$PROJECT_DIR$/.idea/modules/mps/project-modelserver-backend/modelix-samples.mps.project-modelserver-backend.iml" />
       <module fileurl="file://$PROJECT_DIR$/.idea/modules/mps/project-mps-backend/modelix-samples.mps.project-mps-backend.iml" filepath="$PROJECT_DIR$/.idea/modules/mps/project-mps-backend/modelix-samples.mps.project-mps-backend.iml" />
+      <module fileurl="file://$PROJECT_DIR$/.idea/modules/rest-api-model-server/modelix-samples.rest-api-model-server.test.iml" filepath="$PROJECT_DIR$/.idea/modules/rest-api-model-server/modelix-samples.rest-api-model-server.test.iml" />
       <module fileurl="file://$PROJECT_DIR$/.idea/modules/spa-dashboard-angular/modelix-samples.spa-dashboard-angular.iml" filepath="$PROJECT_DIR$/.idea/modules/spa-dashboard-angular/modelix-samples.spa-dashboard-angular.iml" />
     </modules>
   </component>
diff --git a/.idea/modules/rest-api-model-server/modelix-samples.rest-api-model-server.test.iml b/.idea/modules/rest-api-model-server/modelix-samples.rest-api-model-server.test.iml
new file mode 100644
index 0000000..17c03c6
--- /dev/null
+++ b/.idea/modules/rest-api-model-server/modelix-samples.rest-api-model-server.test.iml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module version="4">
+  <component name="AdditionalModuleElements">
+    <content url="file://$MODULE_DIR$/../../../rest-api-model-server/src/test" dumb="true">
+      <sourceFolder url="file://$MODULE_DIR$/../../../rest-api-model-server/src/test/kotlin" isTestSource="true" />
+    </content>
+  </component>
+</module>
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index a8d63a6..a5013ab 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -19,7 +19,7 @@ modelixCore = "3.11.0"
 mpsModelServerSyncPlugin = "2021.2.157"
 
 # backend 1 / SPA
-ktor = "2.3.5"
+ktor = "2.3.6"
 
 # backend 2
 # When increasing the version of quarkus,
@@ -67,6 +67,9 @@ ktor-server-cors = { group = "io.ktor", name = "ktor-server-cors", version.ref =
 ktor-server-websockets = { group = "io.ktor", name = "ktor-server-websockets", version.ref = "ktor" }
 ktor-client-cio = { group = "io.ktor", name = "ktor-client-cio", version.ref = "ktor" }
 ktor-client-core = { group = "io.ktor", name = "ktor-client-core", version.ref = "ktor" }
+ktor-client-content-negotiation = { group = "io.ktor", name = "ktor-client-content-negotiation", version.ref = "ktor" }
+ktor-client-auth = { group = "io.ktor", name = "ktor-client-auth", version.ref = "ktor" }
+ktor-serialization-json = { group = "io.ktor", name = "ktor-serialization-kotlinx-json", version.ref = "ktor" }
 
 # other
 ant-junit = { group = "org.apache.ant", name = "ant-junit", version.ref = "antJunit" }
diff --git a/rest-api-model-server/build.gradle.kts b/rest-api-model-server/build.gradle.kts
index 879b180..f0d2b6c 100644
--- a/rest-api-model-server/build.gradle.kts
+++ b/rest-api-model-server/build.gradle.kts
@@ -19,8 +19,26 @@ dependencies {
     testImplementation("io.quarkus:quarkus-junit5")
     testImplementation("io.rest-assured:rest-assured")
 
-    implementation(libs.ktor.client.core)
     implementation(libs.modelix.model.client)
+    implementation(libs.ktor.client.core)
+    constraints {
+        // The Ktor version 2.3.5 from the modelix release 23.2,
+        // has a bug that makes it break for Quarkus.
+        //
+        // The bug stems from an upgraded Kotlin version,
+        // which broke backward compatibility.
+        // See https://youtrack.jetbrains.com/issue/KTOR-6354
+        //
+        // The Ktor version 2.3.6 provides a fix,
+        // but that Ktor version is not used in modelix release 23.2.
+        //
+        // Because of that, we are explicitly constraining the Ktor version
+        // of Ktor libraries to 2.3.6 or later (specified in libs.version.toml)
+        implementation(libs.ktor.client.cio)
+        implementation(libs.ktor.client.auth)
+        implementation(libs.ktor.client.content.negotiation)
+        implementation(libs.ktor.serialization.json)
+    }
 
     implementation(project(":mps:metamodel-api-kts"))
 }
diff --git a/rest-api-model-server/src/test/kotlin/ReplicatedRepositoryInstantiationTest.kt b/rest-api-model-server/src/test/kotlin/ReplicatedRepositoryInstantiationTest.kt
new file mode 100644
index 0000000..20fab89
--- /dev/null
+++ b/rest-api-model-server/src/test/kotlin/ReplicatedRepositoryInstantiationTest.kt
@@ -0,0 +1,40 @@
+package org.acme.getting.started.testing
+
+import io.quarkus.test.junit.QuarkusTest
+import io.quarkus.test.junit.QuarkusTestProfile
+import io.quarkus.test.junit.TestProfile
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Test
+import org.modelix.model.client.ReplicatedRepository
+import javax.inject.Inject
+
+class UnreachableUrlProfile : QuarkusTestProfile {
+    override fun getConfigOverrides(): Map<String, String> {
+        // Override the server uri to be an unreachable URL.
+        return mapOf("modelix.client.server-uri" to "http://non_existing_host:93939")
+    }
+}
+
+@QuarkusTest
+@TestProfile(value = UnreachableUrlProfile::class)
+class ReplicatedRepositoryInstantiationTest {
+    @Inject
+    lateinit var replicatedRepository: ReplicatedRepository
+
+    @Test
+    fun testInjection() {
+        // This tests, whether `replicatedRepository` can be correctly injected and instantiated by Quarkus.
+        // The actual instantiation is happening when we call something on `replicatedRepository`.
+        // Therefore, we call `.branch`.
+        // The asserted exception message indicates that the `replicatedRepository` was injected correctly.
+        // The exception message "java.lang.NoClassDefFoundError: kotlin/enums/EnumEntriesKt", for example,
+        // would indicate that something is set up wrong and the instantiation is failing.
+        // In the past, we had such issues with the wrong version of Kotlin and Ktor.
+        val exception = assertThrows(RuntimeException::class.java) { replicatedRepository.branch }
+        assertEquals(
+            "Unable to connect to 'http://non_existing_host:93939/get/branch_courses_master' to get key branch_courses_master",
+            exception.message
+        )
+    }
+}
\ No newline at end of file