diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6cbfc4cf..46b24b69 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## 1.5.5
+
+* fixed iam auth for PHP < 8.0
 * added examples
 * updated saveToken function in Iam.php
 
diff --git a/src/Auth/IamAuth.php b/src/Auth/IamAuth.php
index 433e8319..e660f7b8 100644
--- a/src/Auth/IamAuth.php
+++ b/src/Auth/IamAuth.php
@@ -11,7 +11,7 @@ abstract class IamAuth extends Auth
      * @return mixed|null
      * @throws Exception
      */
-    public function requestToken($request_data): mixed
+    public function requestToken($request_data)
     {
         $this->logger()->info('YDB: Obtaining new IAM token...');
 
diff --git a/src/Ydb.php b/src/Ydb.php
index 2ef586f6..19fa6202 100644
--- a/src/Ydb.php
+++ b/src/Ydb.php
@@ -8,7 +8,7 @@ class Ydb
 {
     use Traits\LoggerTrait;
 
-    const VERSION = '1.5.0';
+    const VERSION = '1.5.5';
 
     /**
      * @var string