diff --git a/notification/src/main/java/de/staropensource/engine/notification/NotificationManager.java b/notification/src/main/java/de/staropensource/engine/notification/NotificationManager.java
index d861cad..496fc45 100644
--- a/notification/src/main/java/de/staropensource/engine/notification/NotificationManager.java
+++ b/notification/src/main/java/de/staropensource/engine/notification/NotificationManager.java
@@ -19,12 +19,12 @@
 
 package de.staropensource.engine.notification;
 
-import de.staropensource.engine.base.type.immutable.ImmutableHashMap;
 import de.staropensource.engine.notification.type.Notification;
 import de.staropensource.engine.notification.type.NotificationState;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -49,14 +49,14 @@ public final class NotificationManager {
     private NotificationManager() {}
 
     /**
-     * Returns an {@link ImmutableHashMap} containing all
+     * Returns an immutable map containing all
      * registered notifications and their current states.
      *
      * @return map of registered notifications
      * @since v1-alpha6
      */
     public static @NotNull Map<@NotNull Notification, @NotNull NotificationState> getNotifications() {
-        return new ImmutableHashMap<>(notifications);
+        return Collections.unmodifiableMap(notifications);
     }
 
     /**