diff --git a/src/FMDataAPI.php b/src/FMDataAPI.php
index cd31ec0..24047eb 100644
--- a/src/FMDataAPI.php
+++ b/src/FMDataAPI.php
@@ -2,14 +2,10 @@
 
 namespace INTERMediator\FileMakerServer\RESTAPI;
 
-use Exception;
-use INTERMediator\FileMakerServer\RESTAPI\PersistentSession\ApcuSessionCache;
-use INTERMediator\FileMakerServer\RESTAPI\PersistentSession\PersistentSession;
-use INTERMediator\FileMakerServer\RESTAPI\PersistentSession\SessionCacheInterface;
-use INTERMediator\FileMakerServer\RESTAPI\Supporting\CommunicationProvider;
 use INTERMediator\FileMakerServer\RESTAPI\Supporting\FileMakerLayout;
 use INTERMediator\FileMakerServer\RESTAPI\Supporting\FileMakerRelation;
-use RuntimeException;
+use INTERMediator\FileMakerServer\RESTAPI\Supporting\CommunicationProvider;
+use Exception;
 
 /**
  * Class FMDataAPI is the wrapper of The REST API in Claris FileMaker Server and FileMaker Cloud for AWS.
@@ -42,12 +38,6 @@ class FMDataAPI
      */
     private CommunicationProvider|null $provider;
 
-    /**
-     * @var null|PersistentSession Keeping the PersistentSession object.
-     * @ignore
-     */
-    private PersistentSession|null $persistentSession = null;
-
     /**
      * FMDataAPI constructor. If you want to activate OAuth authentication, $user and $password are set as
      * oAuthRequestId and oAuthIdentifier. Moreover, call useOAuth method before accessing layouts.
@@ -68,8 +58,6 @@ class FMDataAPI
      * Ex.  [{"database"=>"<databaseName>", "username"=>"<username>", "password"=>"<password>"}].
      * If you use OAuth, "oAuthRequestId" and "oAuthIdentifier" keys have to be specified.
      * @param boolean $isUnitTest If it's set to true, the communication provider just works locally.
-     * @param SessionCacheInterface|null $sessionCache Cache backend for persistent sessions. If omitted, APCu will be
-     * used if available, otherwise, no caching will be used.
      */
     public function __construct(string      $solution,
                                 string      $user,
@@ -78,8 +66,7 @@ public function __construct(string      $solution,
                                 int|null    $port = null,
                                 string|null $protocol = null,
                                 array|null  $fmDataSource = null,
-                                bool        $isUnitTest = false,
-                                SessionCacheInterface|null $sessionCache = null)
+                                bool        $isUnitTest = false)
     {
         if (is_null($password)) {
             $password = "password"; // For testing purpose.
@@ -89,14 +76,6 @@ public function __construct(string      $solution,
         } else {
             $this->provider = new Supporting\TestProvider($solution, $user, $password, $host, $port, $protocol, $fmDataSource);
         }
-
-        if ($sessionCache !== null) {
-            $this->persistentSession = new PersistentSession($sessionCache, $solution, $user);
-            $this->provider->keepPersistentSession = true;
-        } elseif (function_exists('apcu_fetch')) {
-            $this->persistentSession = new PersistentSession(new ApcuSessionCache(), $solution, $user);
-            $this->provider->keepPersistentSession = true;
-        }
     }
 
     /**
@@ -210,9 +189,9 @@ public function getFieldHTMLEncoding(): bool
 
     /**
      * Set session token
-     * @param string|null $value The session token.
+     * @param string $value The session token.
      */
-    public function setSessionToken(string|null $value): void
+    public function setSessionToken(string $value): void
     {
         $this->provider->accessToken = $value;
     }
@@ -314,109 +293,6 @@ public function endCommunication(): void
         $this->provider->logout();
     }
 
-    /**
-     * Begin a persistent session which is a serial calling of any database operations, and keep the session token.
-     *
-     * This persistent session persists between multiple PHP requests.
-     * @throws Exception
-     */
-    public function beginPersistentSession(): void
-    {
-        if ($this->persistentSession === null) {
-            throw new RuntimeException(
-                "Persistent sessions require a cache backend. Install ext-apcu or provide a SessionCacheInterface implementation."
-            );
-        }
-
-        try {
-            if (!$this->persistentSession->applyCachedSessionToken($this)) {
-                if ($this->provider->login()) {
-                    $this->persistentSession->cacheCurrentSessionToken($this);
-                }
-            }
-            $this->provider->keepPersistentSession = true;
-        } catch (Exception $e) {
-            $this->persistentSession->clearCachedSessionToken();
-            $this->setSessionToken(null);
-            $this->provider->keepPersistentSession = false;
-            throw $e;
-        }
-    }
-
-    /**
-     * End a persistent session which is a serial calling of any database operations, and logout.
-     * @throws Exception
-     */
-    public function closePersistentSession(): void
-    {
-        if ($this->persistentSession !== null) {
-            $this->persistentSession->clearCachedSessionToken();
-        }
-        $this->provider->keepPersistentSession = false;
-        $this->provider->logout();
-    }
-
-    /**
-     * Execute a callback with this FMDataAPI instance.
-     *
-     * When persistent sessions are enabled, this method uses the cached session when available. If the session is no
-     * longer valid, it creates and caches a new one, then retries the callback once.
-     *
-     * When persistent sessions are not enabled, the callback is invoked immediately with this instance.
-     *
-     * Example:
-     * <code>
-     * $client = new FMDataAPI('MySolution', 'MyUser', 'MyPassword');
-     * $result = $client->execute(
-     *     fn (FMDataAPI $fm) => $fm->layout('MyLayout')->query(
-     *         // do stuff
-     *     )
-     * );
-     * </code>
-     *
-     * @template TReturn
-     * @param callable(FMDataAPI): TReturn $fn
-     * @return TReturn
-     * @throws Exception Any exception thrown by the callback or the underlying provider.
-     */
-    public function execute(callable $fn)
-    {
-        if (!$this->provider->keepPersistentSession || $this->persistentSession === null) {
-            return $fn($this);
-        }
-
-        if ($this->provider->throwExceptionInError) {
-            try {
-                return $fn($this);
-            } catch (Exception $e) {
-                if ($this->errorCode() == 952) {
-                    $this->refreshSession();
-                    return $fn($this);
-                }
-                throw $e;
-            }
-        }
-
-        $result = $fn($this);
-        if ($this->errorCode() == 952) {
-            $this->refreshSession();
-            return $fn($this);
-        }
-        return $result;
-    }
-
-    /**
-     * Clear the current persistent session state, log in again, and cache the refreshed session token.
-     * @throws Exception
-     */
-    private function refreshSession(): void
-    {
-        $this->persistentSession->clearCachedSessionToken();
-        $this->setSessionToken(null);
-        $this->provider->login();
-        $this->persistentSession->cacheCurrentSessionToken($this);
-    }
-
     /**
      * Set the value to the global field.
      * @param array $fields Associated array contains the global field names (Field names must be Fully Qualified) and its values.
diff --git a/src/PersistentSession/ApcuSessionCache.php b/src/PersistentSession/ApcuSessionCache.php
deleted file mode 100644
index 2ee8c68..0000000
--- a/src/PersistentSession/ApcuSessionCache.php
+++ /dev/null
@@ -1,31 +0,0 @@
-<?php
-
-namespace INTERMediator\FileMakerServer\RESTAPI\PersistentSession;
-
-use RuntimeException;
-
-class ApcuSessionCache implements SessionCacheInterface
-{
-  public function __construct()
-  {
-    if (!function_exists('apcu_fetch')) {
-      throw new RuntimeException("APCu is required to use ApcuSessionCache.");
-    }
-  }
-
-  public function get(string $key): string|false
-  {
-    $value = apcu_fetch($key);
-    return is_string($value) ? $value : false;
-  }
-
-  public function set(string $key, string $value, int $ttl): void
-  {
-    apcu_store($key, $value, $ttl);
-  }
-
-  public function delete(string $key): void
-  {
-    apcu_delete($key);
-  }
-}
diff --git a/src/PersistentSession/PersistentSession.php b/src/PersistentSession/PersistentSession.php
deleted file mode 100644
index 0944333..0000000
--- a/src/PersistentSession/PersistentSession.php
+++ /dev/null
@@ -1,120 +0,0 @@
-<?php
-
-namespace INTERMediator\FileMakerServer\RESTAPI\PersistentSession;
-
-use INTERMediator\FileMakerServer\RESTAPI\FMDataAPI;
-use RuntimeException;
-
-/**
- * Class PersistentSession is the wrapper of persistent sessions.
- * The object of this class is going to be generated by the FMDataAPI class,
- * and you shouldn't call the constructor of this class.
- *
- * @package INTER-Mediator\FileMakerServer\RESTAPI\PersistentSession
- * @link https://github.com/msyk/FMDataAPI GitHub Repository
- * @version 36
- */
-class PersistentSession
-{
-    /**
-     * @var int
-     * @ignore
-     */
-    private const TOKEN_TTL = 840;
-
-    /**
-     * @var SessionCacheInterface Cache backend for persistent sessions.
-     * @ignore
-     */
-    private SessionCacheInterface $cache;
-    /**
-     * @var string Database name.
-     * @ignore
-     */
-    private string $database;
-    /**
-     * @var string User name.
-     * @ignore
-     */
-    private string $user;
-
-    /**
-     * @param SessionCacheInterface $cache
-     * @param string $database Database name.
-     * @param string $user User name.
-     */
-    public function __construct(
-        SessionCacheInterface $cache,
-        string                $database,
-        string                $user)
-    {
-        $this->cache = $cache;
-        $this->database = $database;
-        $this->user = $user;
-    }
-
-    /**
-     * Apply the cached session token to the FMDataAPI object if it exists.
-     *
-     * @param FMDataAPI $client The FMDataAPI object.
-     * @return bool True if the cached session token was applied.
-     */
-    public function applyCachedSessionToken(FMDataAPI $client): bool
-    {
-        $token = $this->getCachedSessionToken();
-        if ($token === false) {
-            return false;
-        }
-        $client->setSessionToken($token);
-        return true;
-    }
-
-    /**
-     * Cache the current session token.
-     *
-     * @param FMDataAPI $client The FMDataAPI object.
-     */
-    public function cacheCurrentSessionToken(FMDataAPI $client): void
-    {
-        $token = $this->getCurrentSessionTokenOrFail($client);
-        $this->cache->set($this->cacheKey(), $token, self::TOKEN_TTL);
-    }
-
-    /**
-     * Clear the cached session token.
-     */
-    public function clearCachedSessionToken(): void
-    {
-        $this->cache->delete($this->cacheKey());
-    }
-
-    /**
-     * Retrieve a cached token. Returns false if the key doesn't exist.
-     * @return string|false
-     */
-    private function getCachedSessionToken(): string|false
-    {
-        return $this->cache->get($this->cacheKey());
-    }
-
-    /**
-     * @param FMDataAPI $client
-     * @return string
-     */
-    private function getCurrentSessionTokenOrFail(FMDataAPI $client): string
-    {
-        $token = $client->getSessionToken();
-        if ($token === null) {
-            throw new RuntimeException("Current session token is not available.");
-        }
-        return $token;
-    }
-
-    /**
-     * @return string
-     */
-    private function cacheKey(): string
-    {
-        return "fm_token:{$this->database}:{$this->user}";
-    }
-}
diff --git a/src/PersistentSession/SessionCacheInterface.php b/src/PersistentSession/SessionCacheInterface.php
deleted file mode 100644
index 173c882..0000000
--- a/src/PersistentSession/SessionCacheInterface.php
+++ /dev/null
@@ -1,26 +0,0 @@
-<?php
-
-namespace INTERMediator\FileMakerServer\RESTAPI\PersistentSession;
-interface SessionCacheInterface
-{
-  /**
-   * Retrieve a cached token.
-   * @param string $key
-   * @return string|false returns the cached token, or false if the key doesn't exist.'
-   */
-  public function get(string $key): string|false;
-
-  /**
-   * Store a token with a TTL in seconds.
-   * @param string $key
-   * @param string $value
-   * @param int $ttl
-   */
-  public function set(string $key, string $value, int $ttl): void;
-
-  /**
-   * Delete a cached token.
-   * @param string $key
-   */
-  public function delete(string $key): void;
-}
diff --git a/src/Supporting/CommunicationProvider.php b/src/Supporting/CommunicationProvider.php
index 709c022..4fcef8a 100644
--- a/src/Supporting/CommunicationProvider.php
+++ b/src/Supporting/CommunicationProvider.php
@@ -148,13 +148,6 @@ class CommunicationProvider
      * @ignore
      */
     public bool $keepAuth = false;
-    /**
-     * @var bool Use persistent session for communication with FileMaker server. A persistent session is when a
-     * communication with FileMaker server is kept open for multiple PHP requests, making all PHP requests share the
-     * same session token.
-     * @ignore
-     */
-    public bool $keepPersistentSession = false;
 
     /**
      * @var bool
@@ -521,7 +514,6 @@ public function login(): bool
                 return true;
             }
         } catch (Exception $e) {
-            $this->storeToProperties();
             $this->accessToken = null;
             throw $e;
         }
@@ -536,7 +528,7 @@ public function login(): bool
      */
     public function logout(): void
     {
-        if ($this->keepAuth || $this->keepPersistentSession) {
+        if ($this->keepAuth) {
             return;
         }
         $params = ["sessions" => $this->accessToken];