diff --git a/lib/Hooks.php b/lib/Hooks.php
index 4000c3f..7c9411c 100644
--- a/lib/Hooks.php
+++ b/lib/Hooks.php
@@ -47,7 +47,6 @@ class Hooks {
 		// TODO: remove this when Owncloud starts encoding oc_appconfig as JSON just like it already encodes most other properties
 		$user = Server::get(IUserSession::class)->getUser();
 		if ($user &&
-			array_key_exists('array', $settings) &&
 			is_array($settings['array']) &&
 			array_key_exists('oc_appconfig', $settings['array'])
 		) {
@@ -84,6 +83,6 @@ class Hooks {
 	}
 
 	private static function isJson(mixed $string): bool {
-		return is_string($string) && is_array(json_decode($string, true)) && (json_last_error() == JSON_ERROR_NONE) ? true : false;
+		return is_string($string) && is_array(json_decode($string, true)) && json_last_error() == JSON_ERROR_NONE;
 	}
 }
diff --git a/lib/Service/BookmarkService.php b/lib/Service/BookmarkService.php
index 45d483d..860e8eb 100644
--- a/lib/Service/BookmarkService.php
+++ b/lib/Service/BookmarkService.php
@@ -19,8 +19,8 @@ use OCA\Epubreader\Db\ReaderEntity;
 class BookmarkService extends Service {
 
 	// "bookmark" name to use for the cursor (current reading position)
-	public const CURSOR = '__CURSOR__';
-	public const bookmark_type = 'bookmark';
+	private const CURSOR = '__CURSOR__';
+	private const BOOKMARK_TYPE = 'bookmark';
 
 	private BookmarkMapper $bookmarkMapper;
 
@@ -85,7 +85,7 @@ class BookmarkService extends Service {
 	 * @param string $value
 	 */
 	public function setCursor(int $fileId, string $value): ReaderEntity {
-		return $this->bookmarkMapper->set($fileId, self::CURSOR, $value, self::bookmark_type);
+		return $this->bookmarkMapper->set($fileId, self::CURSOR, $value, self::BOOKMARK_TYPE);
 	}
 
 	/**
@@ -107,6 +107,6 @@ class BookmarkService extends Service {
 	 * @param int $fileId
 	 */
 	public function deleteCursor(int $fileId): void {
-		$this->delete($fileId, self::CURSOR, self::bookmark_type);
+		$this->delete($fileId, self::CURSOR, self::BOOKMARK_TYPE);
 	}
 }
diff --git a/lib/Service/PreferenceService.php b/lib/Service/PreferenceService.php
index adbc03b..7ceb5e8 100644
--- a/lib/Service/PreferenceService.php
+++ b/lib/Service/PreferenceService.php
@@ -20,7 +20,7 @@ class PreferenceService extends Service {
 
 	// (ab)use the fact that $fileId never goes below 1 by using the
 	// value 0 to indicate a default preference
-	public const DEFAULTS = 0;
+	private const DEFAULTS = 0;
 
 	private PreferenceMapper $preferenceMapper;