diff --git a/CHANGELOG.md b/CHANGELOG.md
index efbf652..c34731c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [3.5.9] - 2026-05-04
+### Added
+- Allow setting the terminal using `checkoutSession`.
+
 ## [3.5.8] - 2026-02-23
 ### Added
 - Add support for `checkoutSession` API method.
diff --git a/src/AbstractApi.php b/src/AbstractApi.php
index e415c70..3a3a239 100644
--- a/src/AbstractApi.php
+++ b/src/AbstractApi.php
@@ -55,7 +55,7 @@ abstract class AbstractApi
     /**
      * PHP API version
      */
-    const PHP_API_VERSION = '3.5.8';
+    const PHP_API_VERSION = '3.5.9';
 
     /**
      * Event dispatcher
diff --git a/src/Api/Payments/CheckoutSession.php b/src/Api/Payments/CheckoutSession.php
index 36dbc7b..ac0edc4 100644
--- a/src/Api/Payments/CheckoutSession.php
+++ b/src/Api/Payments/CheckoutSession.php
@@ -29,6 +29,7 @@
 use Altapay\Exceptions\ResponseMessageException;
 use Altapay\Serializer\ResponseSerializer;
 use Altapay\Response\CheckoutSessionResponse;
+use Altapay\Traits\TerminalTrait;
 use GuzzleHttp\Exception\ClientException as GuzzleHttpClientException;
 use GuzzleHttp\Exception\GuzzleException;
 use GuzzleHttp\Psr7\Request;
@@ -37,6 +38,7 @@
 
 class CheckoutSession extends AbstractApi
 {
+    use TerminalTrait;
     /**
      * Set the list of terminals available for the user
      *
@@ -131,7 +133,7 @@ public function setConfig(array $config)
     protected function configureOptions(OptionsResolver $resolver)
     {
         $resolver->setRequired(['terminals']);
-        $resolver->setDefined(['session_id', 'shop_orderid', 'amount', 'currency', 'config']);
+        $resolver->setDefined(['session_id', 'shop_orderid', 'amount', 'currency', 'config', 'terminal']);
         $resolver->addAllowedTypes('terminals', 'array');
         $resolver->addAllowedTypes('session_id', 'string');
         $resolver->addAllowedTypes('shop_orderid', 'string');