diff --git a/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterResource.java b/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterResource.java
index 3786c9c..948ef4b 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterResource.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterResource.java
@@ -55,7 +55,7 @@
     var mailText = Templates.registrationMail(subscription.registrationKey);
     var sendJob = mailText.subject("MulkCMS newsletter registration").to(email).send();
     var page = Templates.completeRegistration().render();
-    return sendJob.thenApply((x) -> page);
+    return sendJob.onItem().transform(x -> page).subscribeAsCompletionStage();
   }
 
   @GET
diff --git a/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterSender.java b/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterSender.java
index 8c8c9b6..1dacccc 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterSender.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterSender.java
@@ -106,7 +106,7 @@
             .to(senderAddress)
             .bcc(subscriberEmails)
             .send();
-    sendJob.toCompletableFuture().get(10000, TimeUnit.SECONDS);
+    sendJob.subscribe().asCompletionStage().get(10000, TimeUnit.SECONDS);
   }
 
   @TemplateExtension
diff --git a/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterUnsubscriber.java b/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterUnsubscriber.java
index 0a67ff6..d157a87 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterUnsubscriber.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/newsletter/NewsletterUnsubscriber.java
@@ -47,7 +47,7 @@
                       .subject("Unsubscribed from MulkCMS newsletter")
                       .to(address)
                       .send();
-              sendJob.toCompletableFuture().get(60, TimeUnit.SECONDS);
+              sendJob.subscribeAsCompletionStage().get(60, TimeUnit.SECONDS);
 
               s.delete();