diff --git a/apps/federatedfilesharing/lib/FederatedShareProvider.php b/apps/federatedfilesharing/lib/FederatedShareProvider.php
index e3731ac3ecf02..8a2c12e0ac8bf 100644
--- a/apps/federatedfilesharing/lib/FederatedShareProvider.php
+++ b/apps/federatedfilesharing/lib/FederatedShareProvider.php
@@ -431,13 +431,7 @@ public function move(IShare $share, $recipient) {
 		return $share;
 	}
 
-	/**
-	 * Get all children of this share
-	 *
-	 * @param IShare $parent
-	 * @return IShare[]
-	 */
-	public function getChildren(IShare $parent) {
+	public function getChildren(IShare $parent): array {
 		$children = [];
 
 		$qb = $this->dbConnection->getQueryBuilder();
diff --git a/apps/sharebymail/lib/ShareByMailProvider.php b/apps/sharebymail/lib/ShareByMailProvider.php
index 16a13786ea1fd..d28f7c51327a9 100644
--- a/apps/sharebymail/lib/ShareByMailProvider.php
+++ b/apps/sharebymail/lib/ShareByMailProvider.php
@@ -637,11 +637,6 @@ protected function generateToken(int $size = 15): string {
 		return $token;
 	}
 
-	/**
-	 * Get all children of this share
-	 *
-	 * @return IShare[]
-	 */
 	public function getChildren(IShare $parent): array {
 		$children = [];
 
diff --git a/build/psalm-baseline.xml b/build/psalm-baseline.xml
index 44e54ae7f5467..5847d0138f3ed 100644
--- a/build/psalm-baseline.xml
+++ b/build/psalm-baseline.xml
@@ -4250,9 +4250,6 @@
       <code><![CDATA[$share->getId()]]></code>
       <code><![CDATA[(int)$data['id']]]></code>
     </InvalidArgument>
-    <UndefinedInterfaceMethod>
-      <code><![CDATA[getParent]]></code>
-    </UndefinedInterfaceMethod>
   </file>
   <file src="lib/private/Share20/Manager.php">
     <InvalidArgument>
@@ -4261,9 +4258,6 @@
     <UndefinedClass>
       <code><![CDATA[\OCA\Circles\Api\v1\Circles]]></code>
     </UndefinedClass>
-    <UndefinedInterfaceMethod>
-      <code><![CDATA[getChildren]]></code>
-    </UndefinedInterfaceMethod>
   </file>
   <file src="lib/private/Share20/ProviderFactory.php">
     <InvalidReturnStatement>
diff --git a/lib/private/Share20/DefaultShareProvider.php b/lib/private/Share20/DefaultShareProvider.php
index a2c0fd15eb4fc..29e7e2b575f99 100644
--- a/lib/private/Share20/DefaultShareProvider.php
+++ b/lib/private/Share20/DefaultShareProvider.php
@@ -127,9 +127,7 @@ public function create(\OCP\Share\IShare $share) {
 				$qb->setValue('expiration', $qb->createNamedParameter($expirationDate, 'datetime'));
 			}
 
-			if (method_exists($share, 'getParent')) {
-				$qb->setValue('parent', $qb->createNamedParameter($share->getParent()));
-			}
+			$qb->setValue('parent', $qb->createNamedParameter($share->getParent()));
 
 			$qb->setValue('hide_download', $qb->createNamedParameter($share->getHideDownload() ? 1 : 0, IQueryBuilder::PARAM_INT));
 		} else {
@@ -358,14 +356,7 @@ public function acceptShare(IShare $share, string $recipient): IShare {
 		return $share;
 	}
 
-	/**
-	 * Get all children of this share
-	 * FIXME: remove once https://github.com/owncloud/core/pull/21660 is in
-	 *
-	 * @param \OCP\Share\IShare $parent
-	 * @return \OCP\Share\IShare[]
-	 */
-	public function getChildren(\OCP\Share\IShare $parent) {
+	public function getChildren(IShare $parent): array {
 		$children = [];
 
 		$qb = $this->dbConn->getQueryBuilder();
diff --git a/lib/private/Share20/LegacyHooks.php b/lib/private/Share20/LegacyHooks.php
index 3bce0b9560ad3..d54c8e3203d17 100644
--- a/lib/private/Share20/LegacyHooks.php
+++ b/lib/private/Share20/LegacyHooks.php
@@ -82,7 +82,7 @@ private function formatHookParams(IShare $share) {
 			'itemSource' => $share->getNodeId(),
 			'shareType' => $shareType,
 			'shareWith' => $sharedWith,
-			'itemparent' => method_exists($share, 'getParent') ? $share->getParent() : '',
+			'itemparent' => $share->getParent(),
 			'uidOwner' => $share->getSharedBy(),
 			'fileSource' => $share->getNodeId(),
 			'fileTarget' => $share->getTarget()
diff --git a/lib/private/Share20/Manager.php b/lib/private/Share20/Manager.php
index 9bfa810b10839..09b27da0a6879 100644
--- a/lib/private/Share20/Manager.php
+++ b/lib/private/Share20/Manager.php
@@ -580,13 +580,10 @@ protected function linkCreateChecks(IShare $share) {
 	 * @param IShare $share
 	 */
 	protected function setLinkParent(IShare $share) {
-		// No sense in checking if the method is not there.
-		if (method_exists($share, 'setParent')) {
-			$storage = $share->getNode()->getStorage();
-			if ($storage->instanceOfStorage(SharedStorage::class)) {
-				/** @var \OCA\Files_Sharing\SharedStorage $storage */
-				$share->setParent($storage->getShareId());
-			}
+		$storage = $share->getNode()->getStorage();
+		if ($storage->instanceOfStorage(SharedStorage::class)) {
+			/** @var \OCA\Files_Sharing\SharedStorage $storage */
+			$share->setParent((int)$storage->getShareId());
 		}
 	}
 
@@ -1008,7 +1005,6 @@ private function setSharePasswordExpirationTime(IShare $share): void {
 
 	/**
 	 * Delete all the children of this share
-	 * FIXME: remove once https://github.com/owncloud/core/pull/21660 is in
 	 *
 	 * @param IShare $share
 	 * @return IShare[] List of deleted shares
diff --git a/lib/private/Share20/Share.php b/lib/private/Share20/Share.php
index 8caabb0898a4a..571efc8c4bef6 100644
--- a/lib/private/Share20/Share.php
+++ b/lib/private/Share20/Share.php
@@ -60,8 +60,7 @@ class Share implements IShare {
 	private $sendPasswordByTalk = false;
 	/** @var string */
 	private $token;
-	/** @var int */
-	private $parent;
+	private ?int $parent = null;
 	/** @var string */
 	private $target;
 	/** @var \DateTime */
@@ -526,25 +525,12 @@ public function getToken() {
 		return $this->token;
 	}
 
-	/**
-	 * Set the parent of this share
-	 *
-	 * @param int $parent
-	 * @return IShare
-	 * @deprecated 12.0.0 The new shares do not have parents. This is just here for legacy reasons.
-	 */
-	public function setParent($parent) {
+	public function setParent(int $parent): self {
 		$this->parent = $parent;
 		return $this;
 	}
 
-	/**
-	 * Get the parent of this share.
-	 *
-	 * @return int
-	 * @deprecated 12.0.0 The new shares do not have parents. This is just here for legacy reasons.
-	 */
-	public function getParent() {
+	public function getParent(): ?int {
 		return $this->parent;
 	}
 
diff --git a/lib/public/Share/IShare.php b/lib/public/Share/IShare.php
index 5d8c64e131462..a1bdb01fcd29d 100644
--- a/lib/public/Share/IShare.php
+++ b/lib/public/Share/IShare.php
@@ -529,6 +529,20 @@ public function setToken($token);
 	 */
 	public function getToken();
 
+	/**
+	 * Set the parent of this share
+	 *
+	 * @since 9.0.0
+	 */
+	public function setParent(int $parent): self;
+
+	/**
+	 * Get the parent of this share.
+	 *
+	 * @since 9.0.0
+	 */
+	public function getParent(): ?int;
+
 	/**
 	 * Set the target path of this share relative to the recipients user folder.
 	 *
diff --git a/lib/public/Share/IShareProvider.php b/lib/public/Share/IShareProvider.php
index 9d7c8013a36ec..23187ca833ef4 100644
--- a/lib/public/Share/IShareProvider.php
+++ b/lib/public/Share/IShareProvider.php
@@ -208,4 +208,12 @@ public function getAccessList($nodes, $currentAccess);
 	 * @since 18.0.0
 	 */
 	public function getAllShares(): iterable;
+
+	/**
+	 * Get all children of this share
+	 *
+	 * @return IShare[]
+	 * @since 9.0.0
+	 */
+	public function getChildren(IShare $parent);
 }