diff --git a/appinfo/app.php b/appinfo/app.php
deleted file mode 100644
index 3a8af3f..0000000
--- a/appinfo/app.php
+++ /dev/null
@@ -1,20 +0,0 @@
-<?php
-
-/**
- * ownCloud - Epubreader App
- *
- * @author Frank de Lange
- * @copyright 2015 - 2017 Frank de Lange
- *
- * This file is licensed under the Affero General Public License version 3 or
- * later.
- */
-
-namespace OCA\Epubreader\AppInfo;
-
-use OCP\Util;
-
-$l = \OC::$server->getL10N('epubreader');
-
-\OCA\Epubreader\Hooks::register();
-Util::addscript('epubreader', 'plugin');
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
new file mode 100644
index 0000000..913555c
--- /dev/null
+++ b/lib/AppInfo/Application.php
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * ownCloud - Epubreader App
+ *
+ * @author Frank de Lange
+ * @copyright 2015 - 2017 Frank de Lange
+ *
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ */
+
+namespace OCA\Epubreader\AppInfo;
+
+use OCA\Epubreader\Hooks;
+use OCP\AppFramework\App;
+use OCP\Util;
+
+class Application extends App {
+
+	public const APP_ID = 'epubreader';
+
+	public function __construct() {
+		parent::__construct(self::APP_ID);
+
+		$l = \OC::$server->getL10N('epubreader');
+		Hooks::register();
+		Util::addscript('epubreader', 'plugin');
+	}
+}
diff --git a/lib/Controller/PageController.php b/lib/Controller/PageController.php
index 13427dd..e91ff0a 100644
--- a/lib/Controller/PageController.php
+++ b/lib/Controller/PageController.php
@@ -75,15 +75,15 @@ class PageController extends Controller {
 		];
 
 		/**
-		 *  $fileInfo = [
-		 *      fileId => null,
-		 *      fileName => null,
-		 *      fileType => null
-		 *  ];
+		 * @var array{
+		 *   fileId: int,
+		 *   fileName: string,
+		 *   fileType: string
+		 * } $fileInfo
 		 */
-		$fileInfo = $this->getFileInfo($this->request->getParam('file'));
+		$fileInfo = $this->getFileInfo((string) $this->request->getParam('file'));
 		$fileId = $fileInfo['fileId'];
-		$type = $this->request->getParam('type');
+		$type = (string) $this->request->getParam('type');
 		$scope = $template = $templates[$type];
 
 		$params = [
@@ -139,7 +139,7 @@ class PageController extends Controller {
 			if ($type == FileInfo::TYPE_FOLDER && $node instanceof Folder) {
 				$query = [];
 				parse_str(parse_url($path, PHP_URL_QUERY), $query);
-				if (isset($query['path'])) {
+				if (isset($query['path']) && is_string($query['path'])) {
 					$node = $node->get($query['path']);
 				} else {
 					throw new NotFoundException('Shared file path or name not set');
@@ -150,11 +150,11 @@ class PageController extends Controller {
 		} else {
 			$filePath = $path;
 			$fileId = $this->rootFolder->getUserFolder($this->userId)
-				->get(preg_replace("/.*\/remote.php\/webdav(.*)/", "$1", rawurldecode($this->request->getParam('file'))))
+				->get(preg_replace("/.*\/remote.php\/webdav(.*)/", "$1", rawurldecode((string) $this->request->getParam('file'))))
 				->getId();
 		}
 
-		/** @var array<string> $pathInfo */
+		/** @var string[] $pathInfo */
 		$pathInfo = pathInfo($filePath);
 
 		return [
diff --git a/lib/Controller/PreferenceController.php b/lib/Controller/PreferenceController.php
index 7505aed..2da664d 100644
--- a/lib/Controller/PreferenceController.php
+++ b/lib/Controller/PreferenceController.php
@@ -57,10 +57,8 @@ class PreferenceController extends Controller {
 	 * @param int $fileId
 	 * @param string $name
 	 * @param string $value
-	 *
-	 * @return array|\OCP\AppFramework\Http\JSONResponse
 	 */
-	public function set(string $scope, int $fileId, string $name, string $value) {
+	public function set(string $scope, int $fileId, string $name, string $value): JSONResponse {
 		return new JSONResponse($this->preferenceService->set($scope, $fileId, $name, $value));
 	}
 
diff --git a/lib/Controller/SettingsController.php b/lib/Controller/SettingsController.php
index 5e82f47..d0759e0 100644
--- a/lib/Controller/SettingsController.php
+++ b/lib/Controller/SettingsController.php
@@ -34,10 +34,10 @@ class SettingsController extends Controller {
 		Config::set('pdf_enable', $PdfEnable);
 		Config::set('cbx_enable', $CbxEnable);
 
-		$response = array(
-			'data' => array('message' => $l->t('Settings updated successfully.')),
+		$response = [
+			'data' => ['message' => $l->t('Settings updated successfully.')],
 			'status' => 'success'
-		);
+		];
 
 		return new JSONResponse($response);
 	}
diff --git a/lib/Db/ReaderEntity.php b/lib/Db/ReaderEntity.php
index a95bc9f..f9bbbc8 100644
--- a/lib/Db/ReaderEntity.php
+++ b/lib/Db/ReaderEntity.php
@@ -12,12 +12,20 @@ namespace OCA\Epubreader\Db;
 
 use OCP\AppFramework\Db\Entity;
 
+/**
+ * @psalm-type SerializedEntity = array<string|int|array>
+ */
 abstract class ReaderEntity extends Entity {
 
 	protected int $lastModified; // modification timestamp
 
-	/* returns decoded json if input is json, otherwise returns input */
+	/**
+	 * returns decoded json if input is json, otherwise returns input
+	 *
+	 * @return string|array
+	 */
 	public static function conditional_json_decode(string $el): mixed {
+		/** @var array $result */
 		$result = json_decode($el);
 		if (json_last_error() === JSON_ERROR_NONE) {
 			return $result;
@@ -34,5 +42,13 @@ abstract class ReaderEntity extends Entity {
 		$this->lastModified = $lastModified;
 	}
 
+	/**
+	 * @psalm-return SerializedEntity
+	 */
 	abstract public function toService(): array;
+
+	/**
+	 * @psalm-return SerializedEntity
+	 */
+	abstract public function jsonSerialize(): array;
 }
diff --git a/lib/Hooks.php b/lib/Hooks.php
index 19bc86e..98bce2f 100644
--- a/lib/Hooks.php
+++ b/lib/Hooks.php
@@ -18,6 +18,7 @@ use OCP\Util;
 class Hooks {
 
 	public static function register(): void {
+		/** @psalm-suppress DeprecatedMethod */
 		Util::connectHook('\OCP\Config', 'js', 'OCA\Epubreader\Hooks', 'announce_settings');
 
 		\OC::$server->getRootFolder()->listen('\OC\Files', 'preDelete', function (Node $node) {
@@ -35,12 +36,20 @@ class Hooks {
 	public static function announce_settings(array $settings): void {
 		// Nextcloud encodes this as JSON, Owncloud does not (yet) (#75)
 		// TODO: rmeove this when Owncloud starts encoding oc_appconfig as JSON just like it already encodes most other properties
-		$isJson = self::isJson($settings['array']['oc_appconfig']);
-		$array = ($isJson) ? json_decode($settings['array']['oc_appconfig'], true) : $settings['array']['oc_appconfig'];
-		$array['filesReader']['enableEpub'] = Config::get('epub_enable', 'true');
-		$array['filesReader']['enablePdf'] = Config::get('pdf_enable', 'true');
-		$array['filesReader']['enableCbx'] = Config::get('cbx_enable', 'true');
-		$settings['array']['oc_appconfig'] = ($isJson) ? json_encode($array) : $array;
+		if (array_key_exists('array', $settings) &&
+			is_array($settings['array']) &&
+			array_key_exists('oc_appconfig', $settings['array'])
+		) {
+			$isJson = self::isJson($settings['array']['oc_appconfig']);
+			/** @var array $array */
+			$array = ($isJson) ? json_decode((string) $settings['array']['oc_appconfig'], true) : $settings['array']['oc_appconfig'];
+			$array['filesReader'] = [
+				'enableEpub' => Config::get('epub_enable', 'true'),
+				'enablePdf' => Config::get('pdf_enable', 'true'),
+				'enableCbx' => Config::get('cbx_enable', 'true'),
+			];
+			$settings['array']['oc_appconfig'] = ($isJson) ? json_encode($array) : $array;
+		}
 	}
 
 	protected static function deleteFile(IDBConnection $connection, int $fileId): void {
diff --git a/lib/Service/BookmarkService.php b/lib/Service/BookmarkService.php
index 19e6654..eacf74b 100644
--- a/lib/Service/BookmarkService.php
+++ b/lib/Service/BookmarkService.php
@@ -13,6 +13,9 @@ namespace OCA\Epubreader\Service;
 use OCA\Epubreader\Db\BookmarkMapper;
 use OCA\Epubreader\Db\ReaderEntity;
 
+/**
+ * @psalm-import-type SerializedEntity from ReaderEntity
+ */
 class BookmarkService extends Service {
 
 	// "bookmark" name to use for the cursor (current reading position)
@@ -34,11 +37,13 @@ class BookmarkService extends Service {
 	 * @param int $fileId
 	 * @param ?string $name
 	 * @param ?string $type
+	 *
+	 * @psalm-return SerializedEntity[]
 	 */
 	public function get($fileId, ?string $name = null, ?string $type = null): array {
 		$result = $this->bookmarkMapper->get($fileId, $name, $type);
 		return array_map(
-			function (ReaderEntity $entity) {
+			function (ReaderEntity $entity): array {
 				return $entity->toService();
 			}, $result);
 	}
@@ -62,9 +67,11 @@ class BookmarkService extends Service {
 	 * @brief get cursor (current position in book)
 	 *
 	 * @param int $fileId
+	 *
+	 * @psalm-return SerializedEntity
 	 */
 	public function getCursor(int $fileId): array {
-		$result = $this->get($fileId, static::CURSOR);
+		$result = $this->get($fileId, self::CURSOR);
 		if (count($result) === 1) {
 			return $result[0];
 		}
@@ -78,7 +85,7 @@ class BookmarkService extends Service {
 	 * @param string $value
 	 */
 	public function setCursor(int $fileId, string $value): ReaderEntity {
-		return $this->bookmarkMapper->set($fileId, static::CURSOR, $value, static::bookmark_type);
+		return $this->bookmarkMapper->set($fileId, self::CURSOR, $value, self::bookmark_type);
 	}
 
 	/**
@@ -100,6 +107,6 @@ class BookmarkService extends Service {
 	 * @param int $fileId
 	 */
 	public function deleteCursor(int $fileId): void {
-		$this->delete($fileId, static::CURSOR, static::bookmark_type);
+		$this->delete($fileId, self::CURSOR, self::bookmark_type);
 	}
 }
diff --git a/lib/Service/PreferenceService.php b/lib/Service/PreferenceService.php
index e3133d1..adbc03b 100644
--- a/lib/Service/PreferenceService.php
+++ b/lib/Service/PreferenceService.php
@@ -13,6 +13,9 @@ namespace OCA\Epubreader\Service;
 use OCA\Epubreader\Db\PreferenceMapper;
 use OCA\Epubreader\Db\ReaderEntity;
 
+/**
+ * @psalm-import-type SerializedEntity from ReaderEntity
+ */
 class PreferenceService extends Service {
 
 	// (ab)use the fact that $fileId never goes below 1 by using the
@@ -39,12 +42,12 @@ class PreferenceService extends Service {
 	 * @param int $fileId
 	 * @param ?string $name
 	 *
-	 * @return array
+	 * @psalm-return SerializedEntity
 	 */
 	public function get(string $scope, int $fileId, ?string $name = null): array {
 		$result = $this->preferenceMapper->get($scope, $fileId, $name);
 		return array_map(
-			function ($entity) {
+			function (ReaderEntity $entity): array {
 				return $entity->toService();
 			}, $result);
 	}
@@ -71,7 +74,7 @@ class PreferenceService extends Service {
 	 * @param ?string $name
 	 */
 	public function getDefault(string $scope, ?string $name = null): array {
-		return $this->get($scope, static::DEFAULTS, $name);
+		return $this->get($scope, self::DEFAULTS, $name);
 	}
 
 	/**
@@ -82,7 +85,7 @@ class PreferenceService extends Service {
 	 * @param string $value
 	 */
 	public function setDefault($scope, $name, $value): ReaderEntity {
-		return $this->preferenceMapper->set($scope, static::DEFAULTS, $name, $value);
+		return $this->preferenceMapper->set($scope, self::DEFAULTS, $name, $value);
 	}
 
 	/**
@@ -107,6 +110,6 @@ class PreferenceService extends Service {
 	 *
 	 */
 	public function deleteDefault(string $scope, ?string $name = null): void {
-		$this->delete($scope, static::DEFAULTS, $name);
+		$this->delete($scope, self::DEFAULTS, $name);
 	}
 }
diff --git a/psalm.xml b/psalm.xml
index c79ee1e..fef7a59 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -34,11 +34,6 @@
                 <referencedClass name="OC" />
             </errorLevel>
         </UndefinedClass>
-        <DeprecatedMethod>
-            <errorLevel type="info">
-                <referencedMethod name="OCP\Util::connectHook" />
-            </errorLevel>
-        </DeprecatedMethod>
         <PropertyNotSetInConstructor errorLevel="suppress" />
     </issueHandlers>
 </psalm>