diff --git a/lib/Db/MatrixTicket.php b/lib/Db/MatrixTicket.php
index b065c0f..6e2d5e2 100644
--- a/lib/Db/MatrixTicket.php
+++ b/lib/Db/MatrixTicket.php
@@ -7,11 +7,11 @@ use OCP\AppFramework\Db\Entity;
 
 class MatrixTicket extends Entity implements JsonSerializable
 {
-	protected $matrixControlRoom;
-	protected $matrixAssistedUser; // The ID of the person who created the ticket. Usually the person who needs help.
-	protected $matrixHelperUser;
-	protected $status;
-	protected $version;
+	protected string $matrixControlRoom;
+	protected string $matrixAssistedUser; // The ID of the person who created the ticket. Usually the person who needs help.
+	protected string $matrixHelperUser;
+	protected string $status;
+	protected int $version;
 
 	public function jsonSerialize(): array
 	{