diff --git a/lib/Action/EmailSync.php b/lib/Action/EmailSync.php
index 9f9ebaa..002d611 100644
--- a/lib/Action/EmailSync.php
+++ b/lib/Action/EmailSync.php
@@ -27,7 +27,7 @@ use OCA\UserSQL\Model\User;
 use OCA\UserSQL\Properties;
 use OCA\UserSQL\Repository\UserRepository;
 use OCP\IConfig;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 
 /**
  * Synchronizes the user email address.
@@ -41,7 +41,7 @@ class EmailSync implements IUserAction
      */
     private $appName;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -61,13 +61,13 @@ class EmailSync implements IUserAction
      * The default constructor.
      *
      * @param string         $appName        The application name.
-     * @param ILogger        $logger         The logger instance.
+     * @param LoggerInterface        $logger         The logger instance.
      * @param Properties     $properties     The properties array.
      * @param IConfig        $config         The config instance.
      * @param UserRepository $userRepository The user repository.
      */
     public function __construct(
-        $appName, ILogger $logger, Properties $properties, IConfig $config,
+        $appName, LoggerInterface $logger, Properties $properties, IConfig $config,
         UserRepository $userRepository
     ) {
         $this->appName = $appName;
diff --git a/lib/Action/NameSync.php b/lib/Action/NameSync.php
index 7b9602e..2c5991f 100644
--- a/lib/Action/NameSync.php
+++ b/lib/Action/NameSync.php
@@ -27,7 +27,7 @@ use OCA\UserSQL\Model\User;
 use OCA\UserSQL\Properties;
 use OCA\UserSQL\Repository\UserRepository;
 use OCP\IConfig;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 
 /**
  * Synchronizes the user name.
@@ -41,7 +41,7 @@ class NameSync implements IUserAction
      */
     private $appName;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -61,13 +61,13 @@ class NameSync implements IUserAction
      * The default constructor.
      *
      * @param string         $appName        The application name.
-     * @param ILogger        $logger         The logger instance.
+     * @param LoggerInterface        $logger         The logger instance.
      * @param Properties     $properties     The properties array.
      * @param IConfig        $config         The config instance.
      * @param UserRepository $userRepository The user repository.
      */
     public function __construct(
-        $appName, ILogger $logger, Properties $properties, IConfig $config,
+        $appName, LoggerInterface $logger, Properties $properties, IConfig $config,
         UserRepository $userRepository
     ) {
         $this->appName = $appName;
diff --git a/lib/Action/QuotaSync.php b/lib/Action/QuotaSync.php
index 699b1e4..5459b02 100644
--- a/lib/Action/QuotaSync.php
+++ b/lib/Action/QuotaSync.php
@@ -27,7 +27,7 @@ use OCA\UserSQL\Model\User;
 use OCA\UserSQL\Properties;
 use OCA\UserSQL\Repository\UserRepository;
 use OCP\IConfig;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 
 /**
  * Synchronizes the user quota.
@@ -41,7 +41,7 @@ class QuotaSync implements IUserAction
      */
     private $appName;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -61,13 +61,13 @@ class QuotaSync implements IUserAction
      * The default constructor.
      *
      * @param string         $appName        The application name.
-     * @param ILogger        $logger         The logger instance.
+     * @param LoggerInterface        $logger         The logger instance.
      * @param Properties     $properties     The properties array.
      * @param IConfig        $config         The config instance.
      * @param UserRepository $userRepository The user repository.
      */
     public function __construct(
-        $appName, ILogger $logger, Properties $properties, IConfig $config,
+        $appName, LoggerInterface $logger, Properties $properties, IConfig $config,
         UserRepository $userRepository
     ) {
         $this->appName = $appName;
diff --git a/lib/Backend/GroupBackend.php b/lib/Backend/GroupBackend.php
index cd61048..01d2e1c 100644
--- a/lib/Backend/GroupBackend.php
+++ b/lib/Backend/GroupBackend.php
@@ -33,7 +33,7 @@ use OCP\Group\Backend\IGroupDetailsBackend;
 use OCP\Group\Backend\IIsAdminBackend;
 use OCP\Group\Backend\ISearchableGroupBackend;
 use OCP\Group\Backend\INamedBackedn;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 use OCP\IUserManager;
 
 use OC\User\LazyUser;
@@ -56,7 +56,7 @@ final class GroupBackend extends ABackend implements
      */
     private $appName;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -77,12 +77,12 @@ final class GroupBackend extends ABackend implements
      *
      * @param string          $AppName         The application name.
      * @param Cache           $cache           The cache instance.
-     * @param ILogger         $logger          The logger instance.
+     * @param LoggerInterface         $logger          The logger instance.
      * @param Properties      $properties      The properties array.
      * @param GroupRepository $groupRepository The group repository.
      */
     public function __construct(
-        $AppName, Cache $cache, ILogger $logger, Properties $properties,
+        $AppName, Cache $cache, LoggerInterface $logger, Properties $properties,
         GroupRepository $groupRepository
     ) {
         $this->appName = $AppName;
diff --git a/lib/Backend/UserBackend.php b/lib/Backend/UserBackend.php
index 1824c4a..c2183bb 100644
--- a/lib/Backend/UserBackend.php
+++ b/lib/Backend/UserBackend.php
@@ -37,7 +37,7 @@ use OCA\UserSQL\Repository\UserRepository;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IConfig;
 use OCP\IL10N;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 use OCP\Security\Events\ValidatePasswordPolicyEvent;
 use OCP\User\Backend\ABackend;
 use OCP\User\Backend\ICheckPasswordBackend;
@@ -69,7 +69,7 @@ final class UserBackend extends ABackend implements
      */
     private $appName;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -106,7 +106,7 @@ final class UserBackend extends ABackend implements
      *
      * @param string           $AppName         The application name.
      * @param Cache            $cache           The cache instance.
-     * @param ILogger          $logger          The logger instance.
+     * @param LoggerInterface          $logger          The logger instance.
      * @param Properties       $properties      The properties array.
      * @param UserRepository   $userRepository  The user repository.
      * @param IL10N            $localization    The localization service.
@@ -114,7 +114,7 @@ final class UserBackend extends ABackend implements
      * @param IEventDispatcher $eventDispatcher The event dispatcher.
      */
     public function __construct(
-        $AppName, Cache $cache, ILogger $logger, Properties $properties,
+        $AppName, Cache $cache, LoggerInterface $logger, Properties $properties,
         UserRepository $userRepository, IL10N $localization, IConfig $config,
         IEventDispatcher $eventDispatcher
     ) {
diff --git a/lib/Cache.php b/lib/Cache.php
index 622deb7..6378004 100644
--- a/lib/Cache.php
+++ b/lib/Cache.php
@@ -26,7 +26,7 @@ use OCA\UserSQL\Constant\App;
 use OCA\UserSQL\Constant\Opt;
 use OCP\ICache;
 use OCP\IConfig;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 
 /**
  * Used to store key-value pairs in the cache memory.
@@ -46,9 +46,9 @@ class Cache
      *
      * @param string  $AppName The application name.
      * @param IConfig $config  The config instance.
-     * @param ILogger $logger  The logger instance.
+     * @param LoggerInterface $logger  The logger instance.
      */
-    public function __construct($AppName, IConfig $config, ILogger $logger)
+    public function __construct($AppName, IConfig $config, LoggerInterface $logger)
     {
         $factory = \OC::$server->getMemCacheFactory();
         $useCache = $config->getAppValue(
diff --git a/lib/Controller/SettingsController.php b/lib/Controller/SettingsController.php
index 8ae3668..42e53a7 100644
--- a/lib/Controller/SettingsController.php
+++ b/lib/Controller/SettingsController.php
@@ -37,7 +37,7 @@ use OCA\UserSQL\Platform\PlatformFactory;
 use OCA\UserSQL\Properties;
 use OCP\AppFramework\Controller;
 use OCP\IL10N;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 use OCP\IRequest;
 use ReflectionClass;
 use ReflectionException;
@@ -50,7 +50,7 @@ use ReflectionException;
 class SettingsController extends Controller
 {
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -71,13 +71,13 @@ class SettingsController extends Controller
      *
      * @param string     $appName      The application name.
      * @param IRequest   $request      An instance of the request.
-     * @param ILogger    $logger       The logger instance.
+     * @param LoggerInterface    $logger       The logger instance.
      * @param IL10N      $localization The localization service.
      * @param Properties $properties   The properties array.
      * @param Cache      $cache        The cache instance.
      */
     public function __construct(
-        $appName, IRequest $request, ILogger $logger, IL10N $localization,
+        $appName, IRequest $request, LoggerInterface $logger, IL10N $localization,
         Properties $properties, Cache $cache
     ) {
         parent::__construct($appName, $request);
diff --git a/lib/Properties.php b/lib/Properties.php
index 762ce3c..db94fb0 100644
--- a/lib/Properties.php
+++ b/lib/Properties.php
@@ -25,7 +25,7 @@ use OCA\UserSQL\Constant\App;
 use OCA\UserSQL\Constant\DB;
 use OCA\UserSQL\Constant\Opt;
 use OCP\IConfig;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 
 /**
  * Store and retrieve application properties.
@@ -48,7 +48,7 @@ class Properties implements \ArrayAccess
      */
     private $config;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -69,11 +69,11 @@ class Properties implements \ArrayAccess
      *
      * @param string  $AppName The application name.
      * @param IConfig $config  The config instance.
-     * @param ILogger $logger  The logger instance.
+     * @param LoggerInterface $logger  The logger instance.
      * @param Cache   $cache   The cache instance.
      */
     public function __construct(
-        $AppName, IConfig $config, ILogger $logger, Cache $cache
+        $AppName, IConfig $config, LoggerInterface $logger, Cache $cache
     ) {
         $this->appName = $AppName;
         $this->config = $config;
diff --git a/lib/Query/DataQuery.php b/lib/Query/DataQuery.php
index 1a7e2ae..b68ae2e 100644
--- a/lib/Query/DataQuery.php
+++ b/lib/Query/DataQuery.php
@@ -28,7 +28,7 @@ use OC\DB\ConnectionFactory;
 use OCA\UserSQL\Constant\DB;
 use OCA\UserSQL\Constant\Query;
 use OCA\UserSQL\Properties;
-use OCP\ILogger;
+use Psr\Log\LoggerInterface;
 
 /**
  * Used to query a database.
@@ -42,7 +42,7 @@ class DataQuery
      */
     private $appName;
     /**
-     * @var ILogger The logger instance.
+     * @var LoggerInterface The logger instance.
      */
     private $logger;
     /**
@@ -62,12 +62,12 @@ class DataQuery
      * The class constructor.
      *
      * @param string        $AppName       The application name.
-     * @param ILogger       $logger        The logger instance.
+     * @param LoggerInterface       $logger        The logger instance.
      * @param Properties    $properties    The properties array.
      * @param QueryProvider $queryProvider The query provider.
      */
     public function __construct(
-        $AppName, ILogger $logger, Properties $properties,
+        $AppName, LoggerInterface $logger, Properties $properties,
         QueryProvider $queryProvider
     ) {
         $this->appName = $AppName;