diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index b4499fec62..1709bd5018 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -29,6 +29,7 @@
 use OCA\Mail\Events\MessageDeletedEvent;
 use OCA\Mail\Events\MessageFlaggedEvent;
 use OCA\Mail\Events\MessageSentEvent;
+use OCA\Mail\Events\NewMessagesSynchronized;
 use OCA\Mail\Events\OutboxMessageCreatedEvent;
 use OCA\Mail\Events\SynchronizationEvent;
 use OCA\Mail\HordeTranslationHandler;
@@ -44,7 +45,6 @@
 use OCA\Mail\Listener\MessageCacheUpdaterListener;
 use OCA\Mail\Listener\MessageKnownSinceListener;
 use OCA\Mail\Listener\MoveJunkListener;
-use OCA\Mail\Listener\NewMessageClassificationListener;
 use OCA\Mail\Listener\NewMessagesNotifier;
 use OCA\Mail\Listener\OauthTokenRefreshListener;
 use OCA\Mail\Listener\OptionalIndicesListener;
@@ -123,10 +123,8 @@ public function register(IRegistrationContext $context): void {
 		$context->registerEventListener(MessageDeletedEvent::class, MessageCacheUpdaterListener::class);
 		$context->registerEventListener(MessageSentEvent::class, AddressCollectionListener::class);
 		$context->registerEventListener(MessageSentEvent::class, InteractionListener::class);
-		$context->registerEventListener(NewMessagesSynchronized::class, NewMessageClassificationListener::class);
 		$context->registerEventListener(NewMessagesSynchronized::class, MessageKnownSinceListener::class);
 		$context->registerEventListener(NewMessagesSynchronized::class, NewMessagesNotifier::class);
-		$context->registerEventListener(MessageSentEvent::class, SaveSentMessageListener::class);
 		$context->registerEventListener(SynchronizationEvent::class, AccountSynchronizedThreadUpdaterListener::class);
 		$context->registerEventListener(UserDeletedEvent::class, UserDeletedListener::class);
 		$context->registerEventListener(NewMessagesSynchronized::class, FollowUpClassifierListener::class);
diff --git a/lib/Db/StatisticsDao.php b/lib/Db/StatisticsDao.php
index 9d3ded4ea6..0b23e0b759 100644
--- a/lib/Db/StatisticsDao.php
+++ b/lib/Db/StatisticsDao.php
@@ -157,7 +157,7 @@ public function getSubjects(array $mailboxes, array $emails): array {
 			->where($qb->expr()->eq('r.type', $qb->createNamedParameter(Address::TYPE_FROM, IQueryBuilder::PARAM_INT), IQueryBuilder::PARAM_INT))
 			->andWhere($qb->expr()->in('m.mailbox_id', $qb->createNamedParameter($mailboxIds, IQueryBuilder::PARAM_INT_ARRAY)))
 			->andWhere($qb->expr()->in('r.email', $qb->createNamedParameter($emails, IQueryBuilder::PARAM_STR_ARRAY), IQueryBuilder::PARAM_STR_ARRAY));
-		$result = $select->execute();
+		$result = $select->executeQuery();
 		$rows = $result->fetchAll();
 		$result->closeCursor();
 		$data = [];
@@ -181,7 +181,7 @@ public function getPreviewTexts(array $mailboxes, array $emails): array {
 			->andWhere($qb->expr()->in('m.mailbox_id', $qb->createNamedParameter($mailboxIds, IQueryBuilder::PARAM_INT_ARRAY)))
 			->andWhere($qb->expr()->in('r.email', $qb->createNamedParameter($emails, IQueryBuilder::PARAM_STR_ARRAY), IQueryBuilder::PARAM_STR_ARRAY))
 			->andWhere($qb->expr()->isNotNull('m.preview_text'));
-		$result = $select->execute();
+		$result = $select->executeQuery();
 		$rows = $result->fetchAll();
 		$result->closeCursor();
 		$data = [];
diff --git a/lib/Service/Classification/FeatureExtraction/SubjectExtractor.php b/lib/Service/Classification/FeatureExtraction/SubjectExtractor.php
index 20dcbeae34..b768938139 100644
--- a/lib/Service/Classification/FeatureExtraction/SubjectExtractor.php
+++ b/lib/Service/Classification/FeatureExtraction/SubjectExtractor.php
@@ -116,8 +116,13 @@ public function extract(Message $message): array {
 	 * Limit feature vector length to actual vocabulary size.
 	 */
 	private function limitFeatureSize(): void {
-		$vocab = $this->wordCountVectorizer->vocabularies()[0];
-		$this->max = count($vocab);
+		$vocabularies = $this->wordCountVectorizer->vocabularies();
+		if (!isset($vocabularies[0])) {
+			// Should not happen but better safe than sorry
+			return;
+		}
+
+		$this->max = count($vocabularies[0]);
 		echo("WCF vocab size: {$this->max}\n");
 	}
 }
diff --git a/lib/Service/Sync/ImapToDbSynchronizer.php b/lib/Service/Sync/ImapToDbSynchronizer.php
index 71fec38a48..e4d0e87474 100644
--- a/lib/Service/Sync/ImapToDbSynchronizer.php
+++ b/lib/Service/Sync/ImapToDbSynchronizer.php
@@ -20,6 +20,7 @@
 use OCA\Mail\Db\MessageMapper as DatabaseMessageMapper;
 use OCA\Mail\Db\Tag;
 use OCA\Mail\Db\TagMapper;
+use OCA\Mail\Events\NewMessagesSynchronized;
 use OCA\Mail\Events\SynchronizationEvent;
 use OCA\Mail\Exception\ClientException;
 use OCA\Mail\Exception\IncompleteSyncException;
@@ -30,7 +31,6 @@
 use OCA\Mail\Exception\UidValidityChangedException;
 use OCA\Mail\IMAP\IMAPClientFactory;
 use OCA\Mail\IMAP\MessageMapper as ImapMessageMapper;
-use OCA\Mail\IMAP\PreviewEnhancer;
 use OCA\Mail\IMAP\Sync\Request;
 use OCA\Mail\IMAP\Sync\Synchronizer;
 use OCA\Mail\Model\IMAPMessage;
@@ -76,7 +76,6 @@ class ImapToDbSynchronizer {
 	/** @var IMailManager */
 	private $mailManager;
 
-	private PreviewEnhancer $previewEnhancer;
 	private TagMapper $tagMapper;
 	private NewMessagesClassifier $newMessagesClassifier;
 
@@ -90,7 +89,6 @@ public function __construct(DatabaseMessageMapper $dbMapper,
 		PerformanceLogger $performanceLogger,
 		LoggerInterface $logger,
 		IMailManager $mailManager,
-		PreviewEnhancer $previewEnhancer,
 		TagMapper $tagMapper,
 		NewMessagesClassifier $newMessagesClassifier) {
 		$this->dbMapper = $dbMapper;
@@ -102,7 +100,6 @@ public function __construct(DatabaseMessageMapper $dbMapper,
 		$this->performanceLogger = $performanceLogger;
 		$this->logger = $logger;
 		$this->mailManager = $mailManager;
-		$this->previewEnhancer = $previewEnhancer;
 		$this->tagMapper = $tagMapper;
 		$this->newMessagesClassifier = $newMessagesClassifier;
 	}