diff --git a/CHANGELOG.md b/CHANGELOG.md
index 190eb08..0ced20b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,25 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [4.0.0] - 2026-04-09
+### Removed
+- deprecated `\Smsapi\Client\Feature\Contacts\Bag\CreateContactBag::withPhone`
+- deprecated `\Smsapi\Client\Feature\Sms\Bag\ScheduleSmsBag::setIdx`
+- deprecated `\Smsapi\Client\Feature\Sms\Bag\SendSmsToGroupBag::setIdx`
+- deprecated `\Smsapi\Client\Feature\Sms\Bag\ScheduleSmsToGroupBag::setIdx`
+- deprecated `\Smsapi\Client\Curl\Exception\RequestException`
+- deprecated `\Smsapi\Client\Curl\Exception\NetworkException`
+- deprecated `\Smsapi\Client\Curl\Exception\ClientException`
+
+## Changed
+- method signature `\Smsapi\Client\Feature\Contacts\ContactsFeature::findContacts`
+- method signature `\Smsapi\Client\Feature\Sms\Bag\ScheduleSmsBag::setExternalId`
+- method signature `\Smsapi\Client\Feature\Sms\Bag\ScheduleSmssBag::setExternalId`
+- method signature `\Smsapi\Client\Feature\Sms\Bag\ScheduleSmsToGroupBag::setExternalId`
+- method signature `\Smsapi\Client\Feature\Sms\Bag\SendSmsBag::setExternalId`
+- method signature `\Smsapi\Client\Feature\Sms\Bag\SendSmssBag::setExternalId`
+- method signature `\Smsapi\Client\Feature\Sms\Bag\SendSmsToGroupBag::setExternalId`
+
 ## [3.0.13] - 2026-01-12
 ### Added
 - PHP-8.5 support
diff --git a/src/Curl/Exception/ClientException.php b/src/Curl/Exception/ClientException.php
deleted file mode 100644
index 0d2726a..0000000
--- a/src/Curl/Exception/ClientException.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Smsapi\Client\Curl\Exception;
-
-use Smsapi\Client\Infrastructure\HttpClient\ClientException as HttpClientException;
-
-/**
- * @api
- * @deprecated
- * @see HttpClientException
- */
-class ClientException extends HttpClientException
-{
-
-}
\ No newline at end of file
diff --git a/src/Curl/Exception/NetworkException.php b/src/Curl/Exception/NetworkException.php
deleted file mode 100644
index 9d1729a..0000000
--- a/src/Curl/Exception/NetworkException.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Smsapi\Client\Curl\Exception;
-
-use Smsapi\Client\Infrastructure\HttpClient\NetworkException as HttpClientNetworkException;
-
-/**
- * @api
- * @deprecated
- * @see HttpClientNetworkException
- */
-class NetworkException extends HttpClientNetworkException
-{
-
-}
\ No newline at end of file
diff --git a/src/Curl/Exception/RequestException.php b/src/Curl/Exception/RequestException.php
deleted file mode 100644
index 0b96f1e..0000000
--- a/src/Curl/Exception/RequestException.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Smsapi\Client\Curl\Exception;
-
-use Smsapi\Client\Infrastructure\HttpClient\RequestException as HttpClientRequestException;
-
-/**
- * @api
- * @deprecated
- * @see HttpClientRequestException
- */
-class RequestException extends HttpClientRequestException
-{
-
-}
\ No newline at end of file
diff --git a/src/Feature/Contacts/Bag/CreateContactBag.php b/src/Feature/Contacts/Bag/CreateContactBag.php
index 54ffd65..7f10579 100644
--- a/src/Feature/Contacts/Bag/CreateContactBag.php
+++ b/src/Feature/Contacts/Bag/CreateContactBag.php
@@ -19,15 +19,6 @@
 #[\AllowDynamicProperties]
 class CreateContactBag
 {
-    /**
-     * @deprecated
-     * @see withPhoneNumber
-     */
-    public static function withPhone(string $phoneNumber): self
-    {
-        return self::withPhoneNumber($phoneNumber);
-    }
-
     public static function withPhoneNumber(string $phoneNumber): self
     {
         $bag = new self();
diff --git a/src/Feature/Sms/Bag/ScheduleSmsBag.php b/src/Feature/Sms/Bag/ScheduleSmsBag.php
index 28a1576..a19332c 100644
--- a/src/Feature/Sms/Bag/ScheduleSmsBag.php
+++ b/src/Feature/Sms/Bag/ScheduleSmsBag.php
@@ -77,19 +77,4 @@ public function setExternalId(string $idx, $checkIdx = null): self
 
         return $this;
     }
-
-    /**
-     * @deprecated
-     * @see ScheduleSmsBag::setExternalId()
-     */
-    /**
-     * @param bool|null $checkIdx
-     */
-    public function setIdx(array $idx, $checkIdx = null): self
-    {
-        $this->idx = $idx;
-        $this->checkIdx = $checkIdx;
-
-        return $this;
-    }
 }
diff --git a/src/Feature/Sms/Bag/ScheduleSmsToGroupBag.php b/src/Feature/Sms/Bag/ScheduleSmsToGroupBag.php
index d10e61f..ec69498 100644
--- a/src/Feature/Sms/Bag/ScheduleSmsToGroupBag.php
+++ b/src/Feature/Sms/Bag/ScheduleSmsToGroupBag.php
@@ -65,19 +65,4 @@ public function setExternalId(string $idx, $checkIdx = null): self
 
         return $this;
     }
-
-    /**
-     * @deprecated
-     * @see ScheduleSmsToGroupBag::setExternalId()
-     */
-    /**
-     * @param bool|null $checkIdx
-     */
-    public function setIdx(array $idx, $checkIdx = null): self
-    {
-        $this->idx = $idx;
-        $this->checkIdx = $checkIdx;
-
-        return $this;
-    }
 }
diff --git a/src/Feature/Sms/Bag/SendSmsToGroupBag.php b/src/Feature/Sms/Bag/SendSmsToGroupBag.php
index fadfbc7..e89f254 100644
--- a/src/Feature/Sms/Bag/SendSmsToGroupBag.php
+++ b/src/Feature/Sms/Bag/SendSmsToGroupBag.php
@@ -58,19 +58,4 @@ public function setExternalId(string $idx, $checkIdx = null): self
 
         return $this;
     }
-
-    /**
-     * @deprecated
-     * @see SendSmsToGroupBag::setExternalId()
-     */
-    /**
-     * @param bool|null $checkIdx
-     */
-    public function setIdx(array $idx, $checkIdx = null): self
-    {
-        $this->idx = $idx;
-        $this->checkIdx = $checkIdx;
-
-        return $this;
-    }
 }
diff --git a/src/SmsapiClient.php b/src/SmsapiClient.php
index 1c2bc2b..8ef1412 100644
--- a/src/SmsapiClient.php
+++ b/src/SmsapiClient.php
@@ -12,7 +12,7 @@
  */
 interface SmsapiClient extends LoggerAwareInterface
 {
-    const VERSION = '3.0.13';
+    const VERSION = '4.0.0';
 
     public function smsapiPlService(string $apiToken): SmsapiPlService;