diff --git a/lib/IFederatedUser.php b/lib/IFederatedUser.php
index 98a19856e..acc43f6c0 100644
--- a/lib/IFederatedUser.php
+++ b/lib/IFederatedUser.php
@@ -75,9 +75,9 @@ public function getDisplayName(): string;
 	public function setBasedOn(?Circle $basedOn): self;
 
 	/**
-	 * @return Circle
+	 * @return ?Circle
 	 */
-	public function getBasedOn(): Circle;
+	public function getBasedOn(): ?Circle;
 
 	/**
 	 * @return bool
diff --git a/lib/Model/FederatedUser.php b/lib/Model/FederatedUser.php
index cb8edc3ff..056768d17 100644
--- a/lib/Model/FederatedUser.php
+++ b/lib/Model/FederatedUser.php
@@ -52,7 +52,7 @@ class FederatedUser extends ManagedModel implements
 	/** @var string */
 	private $displayName = '';
 
-	/** @var Circle */
+	/** @var ?Circle */
 	private $basedOn;
 
 	/** @var int */
@@ -195,9 +195,9 @@ public function setBasedOn(?Circle $basedOn): self {
 	}
 
 	/**
-	 * @return Circle
+	 * @return ?Circle
 	 */
-	public function getBasedOn(): Circle {
+	public function getBasedOn(): ?Circle {
 		return $this->basedOn;
 	}
 
diff --git a/lib/Model/Member.php b/lib/Model/Member.php
index 02e02b5d4..e8682db4c 100644
--- a/lib/Model/Member.php
+++ b/lib/Model/Member.php
@@ -118,7 +118,7 @@ class Member extends ManagedModel implements
 	/** @var int */
 	private $userType = 0;
 
-	/** @var Circle */
+	/** @var ?Circle */
 	private $basedOn;
 
 	/** @var Member */
@@ -384,9 +384,9 @@ public function setBasedOn(?Circle $basedOn): self {
 	}
 
 	/**
-	 * @return Circle
+	 * @return ?Circle
 	 */
-	public function getBasedOn(): Circle {
+	public function getBasedOn(): ?Circle {
 		return $this->basedOn;
 	}
 
@@ -721,7 +721,7 @@ public function getLink(string $singleId, bool $detailed = false): Membership {
 		if ($singleId !== '') {
 			$this->getManager()->getLink($this, $singleId, $detailed);
 		}
-		
+
 		throw new MembershipNotFoundException();
 	}