diff --git a/lib/Activity/DeckProvider.php b/lib/Activity/DeckProvider.php
index 10e01121c..baff9cd5b 100644
--- a/lib/Activity/DeckProvider.php
+++ b/lib/Activity/DeckProvider.php
@@ -29,6 +29,7 @@ use OCA\Deck\Db\Acl;
 use OCP\Activity\IEvent;
 use OCP\Activity\IProvider;
 use OCP\Comments\IComment;
+use OCP\Comments\ICommentsManager;
 use OCP\Comments\NotFoundException;
 use OCP\IURLGenerator;
 use OCP\IUserManager;
@@ -43,11 +44,14 @@ class DeckProvider implements IProvider {
 	private $activityManager;
 	/** @var IUserManager */
 	private $userManager;
+	/** @var ICommentsManager */
+	private $commentsManager;
 
-	public function __construct(IURLGenerator $urlGenerator, ActivityManager $activityManager, IUserManager $userManager, $userId) {
+	public function __construct(IURLGenerator $urlGenerator, ActivityManager $activityManager, IUserManager $userManager, ICommentsManager $commentsManager, $userId) {
 		$this->userId = $userId;
 		$this->urlGenerator = $urlGenerator;
 		$this->activityManager = $activityManager;
+		$this->commentsManager = $commentsManager;
 		$this->userManager = $userManager;
 	}
 
@@ -237,7 +241,7 @@ class DeckProvider implements IProvider {
 		if (array_key_exists('comment', $subjectParams)) {
 			/** @var IComment $comment */
 			try {
-				$comment = \OC::$server->getCommentsManager()->get((int)$subjectParams['comment']);
+				$comment = $this->commentsManager->get((int)$subjectParams['comment']);
 				$event->setParsedMessage($comment->getMessage());
 			} catch (NotFoundException $e) {
 			}
diff --git a/lib/Service/CardService.php b/lib/Service/CardService.php
index 78e957383..554650837 100644
--- a/lib/Service/CardService.php
+++ b/lib/Service/CardService.php
@@ -37,6 +37,7 @@ use OCA\Deck\Db\LabelMapper;
 use OCA\Deck\NotFoundException;
 use OCA\Deck\StatusException;
 use OCA\Deck\BadRequestException;
+use OCP\Comments\ICommentsManager;
 
 class CardService {
 
@@ -51,6 +52,7 @@ class CardService {
 	private $attachmentService;
 	private $currentUser;
 	private $activityManager;
+	private $commentsManager;
 
 	public function __construct(
 		CardMapper $cardMapper,
@@ -63,6 +65,7 @@ class CardService {
 		AssignedUsersMapper $assignedUsersMapper,
 		AttachmentService $attachmentService,
 		ActivityManager $activityManager,
+		ICommentsManager $commentsManager,
 		$userId
 	) {
 		$this->cardMapper = $cardMapper;
@@ -75,6 +78,7 @@ class CardService {
 		$this->assignedUsersMapper = $assignedUsersMapper;
 		$this->attachmentService = $attachmentService;
 		$this->activityManager = $activityManager;
+		$this->commentsManager = $commentsManager;
 		$this->currentUser = $userId;
 	}
 
@@ -83,8 +87,6 @@ class CardService {
 		$card->setAssignedUsers($this->assignedUsersMapper->find($cardId));
 		$card->setLabels($this->labelMapper->findAssignedLabelsForCard($cardId));
 		$card->setAttachmentCount($this->attachmentService->count($cardId));
-		/** @var ICommentsManager commentsManager */
-		$this->commentsManager = \OC::$server->getCommentsManager();
 		$lastRead = $this->commentsManager->getReadMark('deckCard', (string)$card->getId(), \OC::$server->getUserSession()->getUser());
 		$count = $this->commentsManager->getNumberOfCommentsForObject('deckCard', (string)$card->getId(), $lastRead);
 		$card->setCommentsUnread($count);