diff --git a/.gitignore b/.gitignore
index c772037..9b29957 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,6 @@
 .idea/
 vendor/
 build/
+runtime/
+cache/
 composer.lock
\ No newline at end of file
diff --git a/composer.json b/composer.json
index e34e893..2f0bb82 100644
--- a/composer.json
+++ b/composer.json
@@ -13,18 +13,18 @@
   "minimum-stability": "dev",
   "prefer-stable": true,
   "require": {
-    "php": "^7.2",
+    "php": "^7.4|^8.0",
     "ext-mbstring": "*",
     "ext-json":"*",
-    "psr/http-client": "*",
-    "psr/http-message": "*",
-    "guzzlehttp/psr7": "~1.7.0"
+    "psr/http-client": "1.0.3",
+    "guzzlehttp/psr7": "2.7.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "~8.5.13",
-    "squizlabs/php_codesniffer": "~3.5.8",
-    "guzzlehttp/guzzle": "~7.2.0",
-    "psr/log": "~1.0"
+    "phpunit/phpunit": "8.5.41",
+    "squizlabs/php_codesniffer": "3.5.8",
+    "vimeo/psalm": "3.18.2",
+    "guzzlehttp/guzzle": "7.9.0",
+    "psr/log": "1.1"
   },
   "autoload": {
     "psr-4": {
diff --git a/examples/regions.php b/examples/regions.php
new file mode 100644
index 0000000..fc8337d
--- /dev/null
+++ b/examples/regions.php
@@ -0,0 +1,16 @@
+<?php
+
+require '../vendor/autoload.php';
+
+$credentials = \Gladyshev\Yandex\Direct\Credentials::clientSandbox(
+    getenv('_TOKEN_')
+);
+
+$client = new \Gladyshev\Yandex\Direct\Client(
+    $credentials,
+    new GuzzleHttp\Client()
+);
+
+$resp = $client->dictionaries->get(['GeoRegions']);
+
+print_r($resp);
diff --git a/src/AbstractService.php b/src/AbstractService.php
index 4427559..ddeae82 100644
--- a/src/AbstractService.php
+++ b/src/AbstractService.php
@@ -1,30 +1,24 @@
 <?php
 
-declare(strict_types=1);
-
 namespace Gladyshev\Yandex\Direct;
 
+use Gladyshev\Yandex\Direct\Exception\ErrorResponseException;
+use GuzzleHttp\Psr7\Request;
+use Psr\Http\Client\ClientInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use StdClass;
+
 abstract class AbstractService implements ServiceInterface
 {
-    /**
-     * @var string
-     */
-    private $serviceName;
-
-    /**
-     * @var \Gladyshev\Yandex\Direct\CredentialsInterface
-     */
-    private $credentials;
-
-    /**
-     * @var \Psr\Http\Client\ClientInterface
-     */
-    private $httpClient;
+    private string $serviceName;
+    private CredentialsInterface $credentials;
+    private ClientInterface $httpClient;
 
     public function __construct(
         string $serviceName,
-        \Gladyshev\Yandex\Direct\CredentialsInterface $credentials,
-        \Psr\Http\Client\ClientInterface $httpClient
+        CredentialsInterface $credentials,
+        ClientInterface $httpClient
     ) {
         $this->serviceName = $serviceName;
         $this->credentials = $credentials;
@@ -33,7 +27,7 @@ public function __construct(
 
     public function call(array $params = []): array
     {
-        $request = new \GuzzleHttp\Psr7\Request(
+        $request = new Request(
             'POST',
             $this->getUri(),
             $this->getHeaders(),
@@ -50,22 +44,16 @@ protected function getServiceName(): string
         return $this->serviceName;
     }
 
-    protected function getCredentials(): \Gladyshev\Yandex\Direct\CredentialsInterface
+    protected function getCredentials(): CredentialsInterface
     {
         return $this->credentials;
     }
 
-    /**
-     * @return string
-     */
     protected function getUri(): string
     {
         return $this->getCredentials()->getBaseUrl() . '/json/v5/' . mb_strtolower($this->getServiceName());
     }
 
-    /**
-     * @return array
-     */
     protected function getHeaders(): array
     {
         $headers = [
@@ -85,14 +73,10 @@ protected function getHeaders(): array
         return $headers;
     }
 
-    /**
-     * @param array $params
-     * @return string
-     */
     protected function getBody(array $params): string
     {
         if (empty($params['params'])) {
-            $params = new \StdClass();
+            $params = new StdClass();
         } else {
             $params['params'] = array_filter($params['params']);
         }
@@ -100,20 +84,15 @@ protected function getBody(array $params): string
         return json_encode($params);
     }
 
-    /**
-     * @param \Psr\Http\Message\RequestInterface $request
-     * @param \Psr\Http\Message\ResponseInterface $response
-     * @return array
-     */
     protected function handleResponse(
-        \Psr\Http\Message\RequestInterface $request,
-        \Psr\Http\Message\ResponseInterface $response
+        RequestInterface $request,
+        ResponseInterface $response
     ): array {
         $contents = $response->getBody()->getContents();
         $parsedBody = json_decode($contents, true);
 
         if (!is_array($parsedBody)) {
-            throw new \Gladyshev\Yandex\Direct\Exception\ErrorResponseException(
+            throw new ErrorResponseException(
                 'Unexpected API response.',
                 $contents,
                 0,
@@ -123,7 +102,7 @@ protected function handleResponse(
         }
 
         if (!empty($parsedBody['error'])) {
-            throw new \Gladyshev\Yandex\Direct\Exception\ErrorResponseException(
+            throw new ErrorResponseException(
                 $parsedBody['error']['error_string'],
                 $parsedBody['error']['error_detail'],
                 (int) $parsedBody['error']['error_code'],
diff --git a/src/Client.php b/src/Client.php
index 4a33b50..fffd83e 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -1,68 +1,81 @@
 <?php
 
-declare(strict_types=1);
-
 namespace Gladyshev\Yandex\Direct;
 
+use Gladyshev\Yandex\Direct\Exception\ServiceNotFoundException;
+use Gladyshev\Yandex\Direct\Service\AdExtensions;
+use Gladyshev\Yandex\Direct\Service\AdGroups;
+use Gladyshev\Yandex\Direct\Service\AdImages;
+use Gladyshev\Yandex\Direct\Service\Ads;
+use Gladyshev\Yandex\Direct\Service\AgencyClients;
+use Gladyshev\Yandex\Direct\Service\AudienceTargets;
+use Gladyshev\Yandex\Direct\Service\BidModifiers;
+use Gladyshev\Yandex\Direct\Service\Bids;
+use Gladyshev\Yandex\Direct\Service\Campaigns;
+use Gladyshev\Yandex\Direct\Service\Changes;
+use Gladyshev\Yandex\Direct\Service\Clients;
+use Gladyshev\Yandex\Direct\Service\Dictionaries;
+use Gladyshev\Yandex\Direct\Service\DynamicTextAdTargets;
+use Gladyshev\Yandex\Direct\Service\KeywordBids;
+use Gladyshev\Yandex\Direct\Service\Keywords;
+use Gladyshev\Yandex\Direct\Service\KeywordsResearch;
+use Gladyshev\Yandex\Direct\Service\Reports;
+use Gladyshev\Yandex\Direct\Service\RetargetingLists;
+use Gladyshev\Yandex\Direct\Service\Sitelinks;
+use Gladyshev\Yandex\Direct\Service\TurboPages;
+use Gladyshev\Yandex\Direct\Service\VCards;
+use Psr\Http\Client\ClientInterface;
+
 /**
- * Yandex.Direct v5 API client implementation
- *
- * @property \Gladyshev\Yandex\Direct\Service\AdExtensions $adExtensions
- * @property \Gladyshev\Yandex\Direct\Service\AdGroups $adGroups
- * @property \Gladyshev\Yandex\Direct\Service\AdImages $adImages
- * @property \Gladyshev\Yandex\Direct\Service\Ads $ads
- * @property \Gladyshev\Yandex\Direct\Service\AgencyClients $agencyClients
- * @property \Gladyshev\Yandex\Direct\Service\AudienceTargets $audienceTargets
- * @property \Gladyshev\Yandex\Direct\Service\BidModifiers $bidModifiers
- * @property \Gladyshev\Yandex\Direct\Service\Bids $bids
- * @property \Gladyshev\Yandex\Direct\Service\Campaigns $campaigns
- * @property \Gladyshev\Yandex\Direct\Service\Changes $changes
- * @property \Gladyshev\Yandex\Direct\Service\Clients $clients
- * @property \Gladyshev\Yandex\Direct\Service\Dictionaries $dictionaries
- * @property \Gladyshev\Yandex\Direct\Service\DynamicTextAdTargets $dynamicTextAdTargets
- * @property \Gladyshev\Yandex\Direct\Service\KeywordBids $keywordBids
- * @property \Gladyshev\Yandex\Direct\Service\Keywords $keywords
- * @property \Gladyshev\Yandex\Direct\Service\KeywordsResearch $keywordsResearch
- * @property \Gladyshev\Yandex\Direct\Service\Reports $reports
- * @property \Gladyshev\Yandex\Direct\Service\RetargetingLists $retargetingLists
- * @property \Gladyshev\Yandex\Direct\Service\Sitelinks $sitelinks
- * @property \Gladyshev\Yandex\Direct\Service\TurboPages $turboPages
- * @property \Gladyshev\Yandex\Direct\Service\VCards $vCards
+ * @property AdExtensions $adExtensions
+ * @property AdGroups $adGroups
+ * @property AdImages $adImages
+ * @property Ads $ads
+ * @property AgencyClients $agencyClients
+ * @property AudienceTargets $audienceTargets
+ * @property BidModifiers $bidModifiers
+ * @property Bids $bids
+ * @property Campaigns $campaigns
+ * @property Changes $changes
+ * @property Clients $clients
+ * @property Dictionaries $dictionaries
+ * @property DynamicTextAdTargets $dynamicTextAdTargets
+ * @property KeywordBids $keywordBids
+ * @property Keywords $keywords
+ * @property KeywordsResearch $keywordsResearch
+ * @property Reports $reports
+ * @property RetargetingLists $retargetingLists
+ * @property Sitelinks $sitelinks
+ * @property TurboPages $turboPages
+ * @property VCards $vCards
  */
 class Client implements ServiceFactoryInterface
 {
     private const SERVICE_NAMESPACE = __NAMESPACE__ . '\\Service\\';
 
     /**
-     * @var \Gladyshev\Yandex\Direct\ServiceInterface[]
+     * @var ServiceInterface[]
      */
-    private $services = [];
+    private array $services = [];
 
-    /**
-     * @var \Gladyshev\Yandex\Direct\CredentialsInterface
-     */
-    private $credentials;
-
-    /**
-     * @var \Psr\Http\Client\ClientInterface
-     */
-    private $httpClient;
+    private CredentialsInterface $credentials;
+    private ClientInterface $httpClient;
 
     public function __construct(
         CredentialsInterface $credentials,
-        \Psr\Http\Client\ClientInterface $httpClient
+        ClientInterface $httpClient
     ) {
         $this->credentials = $credentials;
         $this->httpClient = $httpClient;
     }
 
-    public function createService(string $serviceName): \Gladyshev\Yandex\Direct\ServiceInterface
+    public function createService(string $serviceName): ServiceInterface
     {
         if (!isset($this->services[$serviceName])) {
             $className = self::SERVICE_NAMESPACE . ucfirst($serviceName);
 
             if (!class_exists($className)) {
-                throw new \Gladyshev\Yandex\Direct\Exception\ServiceNotFoundException(
+                throw new ServiceNotFoundException(
                     $serviceName,
                     "Class '{$className}' is not found."
                 );
@@ -70,8 +83,8 @@ public function createService(string $serviceName): \Gladyshev\Yandex\Direct\Ser
 
             $classInstance = new $className($serviceName, $this->credentials, $this->httpClient);
 
-            if (!$classInstance instanceof \Gladyshev\Yandex\Direct\ServiceInterface) {
-                throw new \Gladyshev\Yandex\Direct\Exception\ServiceNotFoundException(
+            if (!$classInstance instanceof ServiceInterface) {
+                throw new ServiceNotFoundException(
                     $serviceName,
                     "Class '{$className}' must be an instance of '\Gladyshev\Yandex\Direct\ServiceInterface'."
                 );
@@ -83,7 +96,7 @@ public function createService(string $serviceName): \Gladyshev\Yandex\Direct\Ser
         return $this->services[$serviceName];
     }
 
-    public function __get(string $serviceName): \Gladyshev\Yandex\Direct\ServiceInterface
+    public function __get(string $serviceName): ServiceInterface
     {
         return $this->createService($serviceName);
     }
diff --git a/src/Credentials.php b/src/Credentials.php
index ba98ed1..154b2cb 100644
--- a/src/Credentials.php
+++ b/src/Credentials.php
@@ -6,17 +6,15 @@
 
 final class Credentials implements \Gladyshev\Yandex\Direct\CredentialsInterface
 {
-    private $token;
-    private $masterToken;
-    private $clientLogin;
-    private $useOperatorUnits;
-    private $isAgency;
-    private $language;
-    private $baseUrl;
+    private string $token;
+    private ?string $masterToken;
+    private ?string $clientLogin;
+    private ?bool $useOperatorUnits;
+    private bool $isAgency;
+    private string $language;
+    private string $baseUrl;
 
     /**
-     * Credentials constructor.
-     *
      * @param string $token                 # OAuth2 токен доступа
      * @param string|null $masterToken      # Токен для финансовых операций (не поддерживается API V5)
      * @param string|null $clientLogin      # Логин клиента Агентства (если isAgency = true, иначе NULL)
@@ -111,57 +109,36 @@ public static function clientSandbox(
         );
     }
 
-    /**
-     * @return string
-     */
     public function getToken(): string
     {
         return $this->token;
     }
 
-    /**
-     * @return string|null
-     */
     public function getMasterToken(): ?string
     {
         return $this->masterToken;
     }
 
-    /**
-     * @return string|null
-     */
     public function getClientLogin(): ?string
     {
         return $this->clientLogin;
     }
 
-    /**
-     * @return bool|null
-     */
     public function getUseOperatorUnits(): ?bool
     {
         return $this->useOperatorUnits;
     }
 
-    /**
-     * @return string
-     */
     public function getLanguage(): string
     {
         return $this->language;
     }
 
-    /**
-     * @return string
-     */
     public function getBaseUrl(): string
     {
         return $this->baseUrl;
     }
 
-    /**
-     * @return bool
-     */
     public function isAgency(): bool
     {
         return $this->isAgency;
diff --git a/src/CredentialsInterface.php b/src/CredentialsInterface.php
index 3f609ea..fb77133 100644
--- a/src/CredentialsInterface.php
+++ b/src/CredentialsInterface.php
@@ -1,12 +1,7 @@
 <?php
 
-declare(strict_types=1);
-
 namespace Gladyshev\Yandex\Direct;
 
-/**
- * Class CredentialsInterface
- */
 interface CredentialsInterface
 {
     public const DEFAULT_BASE_URL = 'https://api.direct.yandex.com';
@@ -17,39 +12,11 @@ interface CredentialsInterface
     public const LANGUAGE_TR = 'tr';
     public const LANGUAGE_UK = 'uk';
 
-    /**
-     * @return string
-     */
     public function getToken(): string;
-
-    /**
-     * @return string
-     */
     public function getClientLogin(): ?string;
-
-    /**
-     * @return string
-     */
     public function getMasterToken(): ?string;
-
-    /**
-     * @return bool
-     */
     public function getUseOperatorUnits(): ?bool;
-
-    /**
-     * @return string
-     */
     public function getLanguage(): string;
-
-    /**
-     * Returns base URL, ex. https://api.direct.yandex.com
-     * @return string
-     */
     public function getBaseUrl(): string;
-
-    /**
-     * @return bool
-     */
     public function isAgency(): bool;
 }
diff --git a/src/ServiceFactoryInterface.php b/src/ServiceFactoryInterface.php
index da4c6b2..ea35b66 100644
--- a/src/ServiceFactoryInterface.php
+++ b/src/ServiceFactoryInterface.php
@@ -1,21 +1,11 @@
 <?php
 
-declare(strict_types=1);
-
 namespace Gladyshev\Yandex\Direct;
 
-/**
- * Interface ServiceFactoryInterface
- *
- * @author Dmitry Gladyshev <gladyshevd@icloud.com>
- */
 interface ServiceFactoryInterface
 {
     /**
      * Create a Service instance by name
-     *
-     * @param $serviceName
-     * @return AbstractService
      */
     public function createService(string $serviceName): ServiceInterface;
 }
diff --git a/src/ServiceInterface.php b/src/ServiceInterface.php
index 43acc2f..dd7396d 100644
--- a/src/ServiceInterface.php
+++ b/src/ServiceInterface.php
@@ -1,7 +1,5 @@
 <?php
 
-declare(strict_types=1);
-
 namespace Gladyshev\Yandex\Direct;
 
 interface ServiceInterface
diff --git a/src/functions.php b/src/functions.php
index 626243b..7728655 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -2,16 +2,17 @@
 
 namespace Gladyshev\Yandex\Direct;
 
+use ReflectionException;
+use ReflectionMethod;
+
 /**
- * @param string $method
- * @return array
- * @throws \ReflectionException
+ * @throws ReflectionException
  */
 function get_param_names(string $method): array
 {
     [$class, $method] = explode('::', $method);
 
-    $refParams = (new \ReflectionMethod($class, $method))->getParameters();
+    $refParams = (new ReflectionMethod($class, $method))->getParameters();
 
     $paramNames = [];