diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Base/HtmlUtils.php b/snappymail/v/0.0.0/app/libraries/MailSo/Base/HtmlUtils.php
index 0300d6c48..10016b29a 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Base/HtmlUtils.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Base/HtmlUtils.php
@@ -82,7 +82,7 @@ abstract class HtmlUtils
 
 		$oDoc->normalizeDocument();
 
-		if (\MailSo\Base\Utils::FunctionCallable('libxml_clear_errors')) {
+		if (\function_exists('libxml_clear_errors')) {
 			\libxml_clear_errors();
 		}
 
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Base/Http.php b/snappymail/v/0.0.0/app/libraries/MailSo/Base/Http.php
index b4d79017f..cd7639bb9 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Base/Http.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Base/Http.php
@@ -80,7 +80,7 @@ class Http
 	{
 		$sServerKey = 'HTTP_'.\strtoupper(\str_replace('-', '_', $sHeader));
 		$sResultHeader = static::GetServer($sServerKey, '');
-		if (!\strlen($sResultHeader) && Utils::FunctionCallable('apache_request_headers')) {
+		if (!\strlen($sResultHeader) && \function_exists('apache_request_headers')) {
 			$sHeaders = \apache_request_headers();
 			if (isset($sHeaders[$sHeader])) {
 				$sResultHeader = $sHeaders[$sHeader];
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php b/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php
index e611e7249..55eb175e2 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Base/Utils.php
@@ -471,7 +471,7 @@ abstract class Utils
 		if (null === $bValidateAction) {
 			$iResetTimer = 0;
 
-			$bValidateAction = static::FunctionCallable('set_time_limit');
+			$bValidateAction = \function_exists('set_time_limit');
 		}
 
 		if ($bValidateAction && $iTimeToReset < $iTime - $iResetTimer) {
@@ -661,24 +661,13 @@ abstract class Utils
 	public static function FunctionsCallable(array $aFunctionNames) : bool
 	{
 		foreach ($aFunctionNames as $sFunctionName) {
-			if (!static::FunctionCallable($sFunctionName)) {
+			if (!\function_exists($sFunctionName)) {
 				return false;
 			}
 		}
 		return true;
 	}
 
-	private static $disabled_functions = null;
-	public static function FunctionCallable(string $sFunctionName) : bool
-	{
-		if (null === static::$disabled_functions) {
-			static::$disabled_functions = \array_map('trim', \explode(',', \ini_get('disable_functions')));
-		}
-		return \function_exists($sFunctionName)
-			&& !\in_array($sFunctionName, static::$disabled_functions);
-//			&& \is_callable($sFunctionName);
-	}
-
 	public static function Sha1Rand(string $sAdditionalSalt = '') : string
 	{
 		return \sha1($sAdditionalSalt . \random_bytes(16));
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Mime/Message.php b/snappymail/v/0.0.0/app/libraries/MailSo/Mime/Message.php
index 161d48a77..7fbd1c93b 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Mime/Message.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Mime/Message.php
@@ -279,7 +279,7 @@ class Message extends Part
 			$sHostName = isset($_SERVER['SERVER_NAME']) ? $_SERVER['SERVER_NAME'] : '';
 		}
 
-		if (empty($sHostName) && \MailSo\Base\Utils::FunctionCallable('php_uname')) {
+		if (empty($sHostName) && \function_exists('php_uname')) {
 			$sHostName = \php_uname('n');
 		}
 
@@ -289,7 +289,7 @@ class Message extends Part
 
 		return '<'.
 			\MailSo\Base\Utils::Sha1Rand($sHostName.
-				(\MailSo\Base\Utils::FunctionCallable('getmypid') ? \getmypid() : '')).'@'.$sHostName.'>';
+				(\function_exists('getmypid') ? \getmypid() : '')).'@'.$sHostName.'>';
 	}
 
 	public function GetRootPart() : Part
diff --git a/snappymail/v/0.0.0/app/libraries/MailSo/Net/NetClient.php b/snappymail/v/0.0.0/app/libraries/MailSo/Net/NetClient.php
index 9196ac534..a4a19472e 100644
--- a/snappymail/v/0.0.0/app/libraries/MailSo/Net/NetClient.php
+++ b/snappymail/v/0.0.0/app/libraries/MailSo/Net/NetClient.php
@@ -144,7 +144,7 @@ abstract class NetClient
 
 		$this->writeLog((\microtime(true) - $this->iStartConnectTime).' (raw connection)', \LOG_DEBUG);
 
-		if ($this->rConnect && \MailSo\Base\Utils::FunctionCallable('stream_set_timeout')) {
+		if ($this->rConnect && \function_exists('stream_set_timeout')) {
 			\stream_set_timeout($this->rConnect, \max(5, $oSettings->timeout));
 		}
 	}
@@ -157,7 +157,7 @@ abstract class NetClient
 	public function EnableCrypto() : void
 	{
 		$bSuccess = false;
-		if ($this->rConnect && \MailSo\Base\Utils::FunctionCallable('stream_socket_enable_crypto')) {
+		if ($this->rConnect && \function_exists('stream_socket_enable_crypto')) {
 			$crypto_method = STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
 			if (\defined('STREAM_CRYPTO_METHOD_TLSv1_3_CLIENT') && OPENSSL_VERSION_NUMBER >= 0x10101000) {
 				$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_3_CLIENT;
@@ -212,7 +212,7 @@ abstract class NetClient
 
 	public function StreamContextParams() : array
 	{
-		return $this->rConnect && \MailSo\Base\Utils::FunctionCallable('stream_context_get_options')
+		return $this->rConnect && \function_exists('stream_context_get_options')
 			? \stream_context_get_params($this->rConnect) : false;
 	}
 
diff --git a/snappymail/v/0.0.0/app/libraries/RainLoop/Actions.php b/snappymail/v/0.0.0/app/libraries/RainLoop/Actions.php
index d5e3b2472..96bcb23c2 100644
--- a/snappymail/v/0.0.0/app/libraries/RainLoop/Actions.php
+++ b/snappymail/v/0.0.0/app/libraries/RainLoop/Actions.php
@@ -138,7 +138,7 @@ class Actions
 			$this->logWrite(
 				'[SM:' . APP_VERSION . '][IP:'
 				. $oHttp->GetClientIp($this->oConfig->Get('labs', 'http_client_ip_check_proxy', false))
-				. '][PID:' . (\MailSo\Base\Utils::FunctionCallable('getmypid') ? \getmypid() : 'unknown')
+				. '][PID:' . (\function_exists('getmypid') ? \getmypid() : 'unknown')
 				. '][' . \MailSo\Base\Http::GetServer('SERVER_SOFTWARE', '~')
 				. '][' . \PHP_SAPI
 				. '][Streams:' . \implode(',', \stream_get_transports())
diff --git a/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/AdminDomains.php b/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/AdminDomains.php
index ad7c647b9..80bad787d 100644
--- a/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/AdminDomains.php
+++ b/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/AdminDomains.php
@@ -142,7 +142,7 @@ trait AdminDomains
 			}
 
 			if ($oDomain->SmtpSettings()->usePhpMail) {
-				$mSmtpResult = \MailSo\Base\Utils::FunctionCallable('mail');
+				$mSmtpResult = \function_exists('mail');
 				if (!$mSmtpResult) {
 					$sSmtpErrorDesc = 'PHP: mail() function is undefined';
 				}
diff --git a/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/Messages.php b/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/Messages.php
index d7453b2a3..bc75d4f33 100644
--- a/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/Messages.php
+++ b/snappymail/v/0.0.0/app/libraries/RainLoop/Actions/Messages.php
@@ -797,7 +797,7 @@ trait Messages
 			$oAccount->SmtpConnectAndLogin($this->Plugins(), $oSmtpClient);
 
 			if ($oSmtpClient->Settings->usePhpMail) {
-				if (!$sFrom || !\MailSo\Base\Utils::FunctionCallable('mail')) {
+				if (!$sFrom || !\function_exists('mail')) {
 					throw new ClientException(Notifications::CantSendMessage);
 				}
 				$oToCollection = $oMessage->GetTo();