diff --git a/3rdParty/fuerte/include/fuerte/connection.h b/3rdParty/fuerte/include/fuerte/connection.h
index ba8380f493..ac98fedaa1 100644
--- a/3rdParty/fuerte/include/fuerte/connection.h
+++ b/3rdParty/fuerte/include/fuerte/connection.h
@@ -52,17 +52,6 @@ class Connection : public std::enable_shared_from_this<Connection> {
   /// @brief Send a request to the server and wait into a response it received.
   std::unique_ptr<Response> sendRequest(std::unique_ptr<Request> r);
 
-  /// @brief sed request synchronously, only save to use if the
-  virtual std::unique_ptr<Response> sendRequestSync(std::unique_ptr<Request> r) {
-    return sendRequest(std::move(r));
-  }
-  
-  // Send a request to the server and wait into a response it received.
-  /*std::unique_ptr<Response> sendRequest(Request const& r) {
-    std::unique_ptr<Request> copy(new Request(r));
-    return sendRequest(std::move(copy));
-  }*/
-
   // Send a request to the server and return immediately.
   // When a response is received or an error occurs, the corresponding
   // callbackis called. The callback is executed on a specific
@@ -70,29 +59,24 @@ class Connection : public std::enable_shared_from_this<Connection> {
   virtual MessageID sendRequest(std::unique_ptr<Request> r,
                                 RequestCallback cb) = 0;
 
-  // Send a request to the server and return immediately.
-  // When a response is received or an error occurs, the corresponding
-  // callback is called.
-  /*MessageID sendRequest(Request const& r, RequestCallback cb) {
-    std::unique_ptr<Request> copy(new Request(r));
-    return sendRequest(std::move(copy), cb);
-  }*/
 
   // Return the number of requests that have not yet finished.
   virtual std::size_t requestsLeft() const = 0;
   
   /// @brief connection state
   virtual State state() const = 0;
-
-  /// @brief Activate the connection.
-  virtual void startConnection() = 0;
-  virtual void shutdownConnection(const ErrorCondition) = 0;
+  
+  /// @brief cancel the connection, unusable afterwards
+  virtual void cancel() = 0;
   
   std::string endpoint() const;
 
  protected:
   Connection(detail::ConnectionConfiguration const& conf)
       : _config(conf) {}
+  
+  /// @brief Activate the connection.
+  virtual void startConnection() = 0;
 
   // Invoke the configured ConnectionFailureCallback (if any)
   void onFailure(Error errorCode, const std::string& errorMessage) {
diff --git a/3rdParty/fuerte/src/AsioSockets.h b/3rdParty/fuerte/src/AsioSockets.h
index f291595874..7bc2b106ff 100644
--- a/3rdParty/fuerte/src/AsioSockets.h
+++ b/3rdParty/fuerte/src/AsioSockets.h
@@ -38,8 +38,10 @@ struct Socket<SocketType::Tcp>  {
     : resolver(ctx), socket(ctx) {}
   
   ~Socket() {
-    resolver.cancel();
-    shutdown();
+    try {
+      resolver.cancel();
+      shutdown();
+    } catch(...) {}
   }
   
   template<typename CallbackT>
@@ -63,10 +65,10 @@ struct Socket<SocketType::Tcp>  {
   }
   void shutdown() {
     if (socket.is_open()) {
-      asio_ns::error_code error; // prevents exceptions
-      socket.cancel(error);
-      socket.shutdown(asio_ns::ip::tcp::socket::shutdown_both, error);
-      socket.close(error);
+      asio_ns::error_code ec; // prevents exceptions
+      socket.cancel(ec);
+      socket.shutdown(asio_ns::ip::tcp::socket::shutdown_both, ec);
+      socket.close(ec);
     }
   }
   
@@ -81,8 +83,10 @@ struct Socket<fuerte::SocketType::Ssl> {
   : resolver(ctx), socket(ctx, loop.sslContext()) {}
   
   ~Socket() {
-    resolver.cancel();
-    shutdown();
+    try {
+      resolver.cancel();
+      shutdown();
+    } catch(...) {}
   }
   
   template<typename CallbackT>
@@ -124,12 +128,10 @@ struct Socket<fuerte::SocketType::Ssl> {
     resolver.async_resolve({config._host, config._port}, rcb);
   }
   void shutdown() {
-    //socket.cancel();
-    if (socket.lowest_layer().is_open()) {
-      asio_ns::error_code error;
-      socket.shutdown(error);
-      socket.lowest_layer().shutdown(asio_ns::ip::tcp::socket::shutdown_both, error);
-      socket.lowest_layer().close(error);
+    if (socket.next_layer().is_open()) {
+      asio_ns::error_code ec;
+      socket.next_layer().shutdown(asio_ns::ip::tcp::socket::shutdown_both, ec);
+      socket.shutdown(ec);
     }
   }
   
diff --git a/3rdParty/fuerte/src/ConnectionBuilder.cpp b/3rdParty/fuerte/src/ConnectionBuilder.cpp
index 706a1d6b76..59920f8301 100644
--- a/3rdParty/fuerte/src/ConnectionBuilder.cpp
+++ b/3rdParty/fuerte/src/ConnectionBuilder.cpp
@@ -63,7 +63,7 @@ std::shared_ptr<Connection> ConnectionBuilder::connect(EventLoopService& loop) {
 #endif
   }
   if (!result) {
-    throw std::logic_error("unsupported socket type");
+    throw std::logic_error("unsupported socket or protocol type");
   }
   
   // Start the connection implementation
diff --git a/3rdParty/fuerte/src/HttpConnection.cpp b/3rdParty/fuerte/src/HttpConnection.cpp
index f50ff82e7f..2e2844e223 100644
--- a/3rdParty/fuerte/src/HttpConnection.cpp
+++ b/3rdParty/fuerte/src/HttpConnection.cpp
@@ -104,7 +104,7 @@ HttpConnection<ST>::HttpConnection(EventLoopService& loop,
   _state(Connection::State::Disconnected),
   _numQueued(0),
   _active(false),
-  _queue(1024) {
+  _queue() {
   // initialize http parsing code
   _parserSettings.on_message_begin = ::on_message_began;
   _parserSettings.on_status = ::on_status;
@@ -141,7 +141,12 @@ MessageID HttpConnection<ST>::sendRequest(std::unique_ptr<Request> req,
                                           RequestCallback cb) {
   static std::atomic<uint64_t> ticketId(1);
   
-  assert(req);
+  Connection::State state = _state.load(std::memory_order_acquire);
+  if (state == Connection::State::Failed) {
+    cb(errorToInt(ErrorCondition::Canceled), std::move(req), nullptr);
+    return 0;
+  }
+  
   // construct RequestItem
   std::unique_ptr<RequestItem> item(new RequestItem());
   // requestItem->_response later
@@ -153,13 +158,12 @@ MessageID HttpConnection<ST>::sendRequest(std::unique_ptr<Request> req,
   // Prepare a new request
   uint64_t id = item->_messageID;
   if (!_queue.push(item.get())) {
-    FUERTE_LOG_ERROR << "connection queue capactiy exceeded\n";
-    throw std::length_error("connection queue capactiy exceeded");
+    FUERTE_LOG_ERROR << "connection queue capacity exceeded\n";
+    throw std::length_error("connection queue capacity exceeded");
   }
   item.release();
   _numQueued.fetch_add(1, std::memory_order_relaxed);
 
-  Connection::State state = _state.load(std::memory_order_acquire);
   if (state == Connection::State::Connected) {
     FUERTE_LOG_HTTPTRACE << "sendRequest (http): start sending & reading\n";
     startWriting();
@@ -173,7 +177,6 @@ MessageID HttpConnection<ST>::sendRequest(std::unique_ptr<Request> req,
 // Activate this connection.
 template <SocketType ST>
 void HttpConnection<ST>::startConnection() {
-  
   // start connecting only if state is disconnected
   Connection::State exp = Connection::State::Disconnected;
   if (!_state.compare_exchange_strong(exp, Connection::State::Connecting)) {
@@ -195,19 +198,38 @@ void HttpConnection<ST>::startConnection() {
   });
 }
   
+/// @brief cancel the connection, unusable afterwards
+template <SocketType ST>
+void HttpConnection<ST>::cancel() {
+  std::weak_ptr<Connection> self = shared_from_this();
+  asio_ns::post(*_io_context, [self, this] {
+    auto s = self.lock();
+    if (s) {
+      shutdownConnection(ErrorCondition::Canceled);
+      _state.store(State::Failed);
+    }
+  });
+}
+
 // shutdown the connection and cancel all pending messages.
 template<SocketType ST>
 void HttpConnection<ST>::shutdownConnection(const ErrorCondition ec) {
   FUERTE_LOG_CALLBACKS << "shutdownConnection\n";
   
-  _state.store(State::Disconnected, std::memory_order_release);
+  if (_state.load() != State::Failed) {
+    _state.store(State::Disconnected);
+  }
+  
+  // cancel timeouts
   try {
-    _timeout.cancel();    // cancel timeouts
+    _timeout.cancel();   
   } catch (...) {
     // cancel() may throw, but we are not allowed to throw here
     // as we may be called from the dtor
   }
-  _protocol.shutdown(); // Close socket
+
+  // Close socket
+  _protocol.shutdown();
   _active.store(false); // no IO operations running
   
   RequestItem* item = nullptr;
@@ -335,7 +357,7 @@ void HttpConnection<ST>::asyncWriteNextRequest() {
       return;
     }
     // a request got queued in-between last minute
-    _active.store(true, std::memory_order_release);
+    _active.store(true);
   }
   std::shared_ptr<http::RequestItem> item(ptr);
   _numQueued.fetch_sub(1, std::memory_order_relaxed);
@@ -505,114 +527,22 @@ template<SocketType ST>
 void HttpConnection<ST>::setTimeout(std::chrono::milliseconds millis) {
   if (millis.count() == 0) {
     _timeout.cancel();
-    return; // do
+    return;
   }
   assert(millis.count() > 0);
   _timeout.expires_after(millis);
-  auto self = shared_from_this();
-  _timeout.async_wait([this, self] (asio_ns::error_code const& e) {
-    if (e == asio_ns::error::operation_aborted) {
-      // timer was canceled
-      return;
-    }
-    
-    if (!e) {  // expired
-      FUERTE_LOG_DEBUG << "HTTP-Request timeout\n";
-      restartConnection(ErrorCondition::Timeout);
+  
+  std::weak_ptr<Connection> self = shared_from_this();
+  _timeout.async_wait([self, this] (asio_ns::error_code const& ec) {
+    if (!ec) {
+      auto s = self.lock();
+      if (s) {
+        FUERTE_LOG_DEBUG << "HTTP-Request timeout\n";
+        restartConnection(ErrorCondition::Timeout);
+      }
     }
   });
 }
-
-/// @brief sed request synchronously, only save to use if the
-template<SocketType ST>
-std::unique_ptr<Response> HttpConnection<ST>::sendRequestSync(std::unique_ptr<Request> req) {
-  int max = 1024;
-  Connection::State state = _state.load(std::memory_order_acquire);
-  while (state != State::Connected && max-- > 0) {
-    if (state == State::Failed) {
-      return nullptr;
-    } else if (state == State::Disconnected) {
-      startConnection();
-    }
-    std::this_thread::sleep_for(std::chrono::milliseconds(1));
-    state = _state.load(std::memory_order_acquire);
-  }
-  if (state != State::Connected) {
-    throw ErrorCondition::CouldNotConnect;
-  }
-  
-  RequestItem item;
-  // requestItem->_response later
-  item._requestHeader = buildRequestBody(*req);
-  item._request = std::move(req);
-  item._response.reset(new Response());
-
-  setTimeout(item._request->timeout());
-  std::vector<asio_ns::const_buffer> buffers(2);
-  buffers.emplace_back(item._requestHeader.data(),
-                       item._requestHeader.size());
-  // GET and HEAD have no payload
-  if (item._request->header.restVerb != RestVerb::Get &&
-      item._request->header.restVerb != RestVerb::Head) {
-    buffers.emplace_back(item._request->payload());
-  }
-  asio_ns::error_code ec;
-  asio_ns::write(_protocol.socket, buffers, ec);
-  if (ec) {
-    auto err = checkEOFError(ec, ErrorCondition::WriteError);;
-    shutdownConnection(err);
-    throw err;
-  }
-  
-  http_parser_init(&_parser, HTTP_RESPONSE);
-  _parser.data = static_cast<void*>(&item);
-  
-  while (!item.message_complete) {
-    // reserve 32kB in output buffer
-    auto mutableBuff = _receiveBuffer.prepare(READ_BLOCK_SIZE);
-    
-    size_t transferred = _protocol.socket.read_some(mutableBuff, ec);
-    if (ec) {
-      auto err = checkEOFError(ec, ErrorCondition::ReadError);;
-      shutdownConnection(err);
-      throw err;
-    }
-    
-    // Inspect the data we've received so far.
-    auto cursor = asio_ns::buffer_cast<const char*>(_receiveBuffer.data()); // no copy
-    
-    /* Start up / continue the parser.
-     * Note we pass recved==0 to signal that EOF has been received.
-     */
-    size_t nparsed = http_parser_execute(&_parser, &_parserSettings,
-                                         cursor, transferred);
-    
-    if (_parser.upgrade || nparsed != transferred) {
-      /* Handle error. Usually just close the connection. */
-      FUERTE_LOG_ERROR << "Invalid HTTP response in parser\n";
-      shutdownConnection(ErrorCondition::ProtocolError);  // will cleanup _inFlight
-      throw ErrorCondition::ProtocolError;
-    }
-
-    // item.message_complete may have been set by the call to http_parser_execute!
-    if (item.message_complete) {
-      //_timeout.cancel(); // got response in time
-      // Remove consumed data from receive buffer.
-      _receiveBuffer.consume(nparsed);
-      
-      // thread-safe access on IO-Thread
-      if (!item._responseBuffer.empty()) {
-        item._response->setPayload(std::move(item._responseBuffer), 0);
-      }
-      if (!item.should_keep_alive) {
-        shutdownConnection(ErrorCondition::CloseRequested);
-      }
-      return std::move(item._response);
-    }
-  }
-  
-  throw ErrorCondition::Timeout;
-}
   
 template class arangodb::fuerte::v1::http::HttpConnection<SocketType::Tcp>;
 template class arangodb::fuerte::v1::http::HttpConnection<SocketType::Ssl>;
diff --git a/3rdParty/fuerte/src/HttpConnection.h b/3rdParty/fuerte/src/HttpConnection.h
index 4eadaa5c9c..43bf78e288 100644
--- a/3rdParty/fuerte/src/HttpConnection.h
+++ b/3rdParty/fuerte/src/HttpConnection.h
@@ -55,9 +55,6 @@ class HttpConnection final : public fuerte::Connection {
   /// Start an asynchronous request.
   MessageID sendRequest(std::unique_ptr<Request>, RequestCallback) override;
   
-  /// @brief sed request synchronously, only save to use if the
-  std::unique_ptr<Response> sendRequestSync(std::unique_ptr<Request> r) override;
-  
   // Return the number of unfinished requests.
   size_t requestsLeft() const override {
     return _numQueued.load(std::memory_order_acquire);
@@ -70,11 +67,15 @@ class HttpConnection final : public fuerte::Connection {
   
   // Activate this connection
   void startConnection() override;
-  
-  // called on shutdown, always call superclass
-  void shutdownConnection(const ErrorCondition) override;
 
+  /// @brief cancel the connection, unusable afterwards
+  void cancel() override;
+  
  private:
+  
+  // shutdown connection, cancel async operations
+  void shutdownConnection(const ErrorCondition);
+  
   // restart connection
   void restartConnection(const ErrorCondition);
   
@@ -124,7 +125,8 @@ class HttpConnection final : public fuerte::Connection {
   std::atomic<bool> _active;
   
   /// elements to send out
-  boost::lockfree::queue<fuerte::v1::http::RequestItem*> _queue;
+  boost::lockfree::queue<fuerte::v1::http::RequestItem*,
+    boost::lockfree::capacity<1024>> _queue;
   
   /// cached authentication header
   std::string _authHeader;
diff --git a/3rdParty/fuerte/src/VstConnection.cpp b/3rdParty/fuerte/src/VstConnection.cpp
index 03e91be83e..0b8ff5a51a 100644
--- a/3rdParty/fuerte/src/VstConnection.cpp
+++ b/3rdParty/fuerte/src/VstConnection.cpp
@@ -49,7 +49,7 @@ VstConnection<ST>::VstConnection(
       _timeout(*_io_context),
       _state(Connection::State::Disconnected),
       _loopState(0),
-      _writeQueue(1024){}
+      _writeQueue() {}
 
 template<SocketType ST>
 VstConnection<ST>::~VstConnection() {
@@ -62,6 +62,12 @@ static std::atomic<MessageID> vstMessageId(1);
 template<SocketType ST>
 MessageID VstConnection<ST>::sendRequest(std::unique_ptr<Request> req,
                                          RequestCallback cb) {
+  Connection::State state = _state.load(std::memory_order_acquire);
+  if (state == Connection::State::Failed) {
+    cb(errorToInt(ErrorCondition::Canceled), std::move(req), nullptr);
+    return 0;
+  }
+  
   // it does not matter if IDs are reused on different connections
   uint64_t mid = vstMessageId.fetch_add(1, std::memory_order_relaxed);
   // Create RequestItem from parameters
@@ -74,14 +80,13 @@ MessageID VstConnection<ST>::sendRequest(std::unique_ptr<Request> req,
   
   // Add item to send queue
   if (!_writeQueue.push(item.get())) {
-    FUERTE_LOG_ERROR << "connection queue capactiy exceeded\n";
-    throw std::length_error("connection queue capactiy exceeded");
+    FUERTE_LOG_ERROR << "connection queue capacity exceeded\n";
+    throw std::length_error("connection queue capacity exceeded");
   }
   item.release();
   // WRITE_LOOP_ACTIVE, READ_LOOP_ACTIVE are synchronized via cmpxchg
   uint32_t loop =  _loopState.fetch_add(WRITE_LOOP_QUEUE_INC, std::memory_order_seq_cst);
   
-  Connection::State state = _state.load(std::memory_order_acquire);
   if (state == Connection::State::Connected) {
     FUERTE_LOG_VSTTRACE << "sendRequest (vst): start sending & reading\n";
     if (!(loop & WRITE_LOOP_ACTIVE)) {
@@ -103,7 +108,6 @@ void VstConnection<ST>::startConnection() {
     FUERTE_LOG_ERROR << "already resolving endpoint\n";
     return;
   }
-  
   auto self = shared_from_this();
   _protocol.connect(_config, [self, this](asio_ns::error_code const& ec) {
     if (ec) {
@@ -117,18 +121,34 @@ void VstConnection<ST>::startConnection() {
   });
 }
   
+/// @brief cancel the connection, unusable afterwards
+template <SocketType ST>
+void VstConnection<ST>::cancel() {
+  std::weak_ptr<Connection> self = shared_from_this();
+  asio_ns::post(*_io_context, [self, this] {
+    auto s = self.lock();
+    if (s) {
+      shutdownConnection(ErrorCondition::Canceled);
+      _state.store(State::Failed);
+    }
+  });
+}
+  
 // shutdown the connection and cancel all pending messages.
 template <SocketType ST>
 void VstConnection<ST>::shutdownConnection(const ErrorCondition ec) {
   FUERTE_LOG_CALLBACKS << "shutdownConnection\n";
   
-  _state.store(State::Disconnected, std::memory_order_release);
+  if (_state.load() != State::Failed) {
+    _state.store(State::Disconnected);
+  }
   
   // cancel timeouts
   try {
     _timeout.cancel();
   } catch (...) {
-    // cancel() may throw
+    // cancel() may throw, but we are not allowed to throw here
+    // as we may be called from the dtor
   }
   
   // Close socket
@@ -199,10 +219,9 @@ void VstConnection<ST>::finishInitialization() {
   auto self = shared_from_this();
   asio_ns::async_write(_protocol.socket,
       asio_ns::buffer(vstHeader, strlen(vstHeader)),
-      [this, self](asio_ns::error_code const& ec, std::size_t transferred) {
+      [self, this](asio_ns::error_code const& ec, std::size_t transferred) {
         if (ec) {
           FUERTE_LOG_ERROR << ec.message() << "\n";
-          _state.store(Connection::State::Disconnected, std::memory_order_release);
           shutdownConnection(ErrorCondition::CouldNotConnect);
           onFailure(errorToInt(ErrorCondition::CouldNotConnect),
                     "unable to initialize connection: error=" + ec.message());
@@ -242,7 +261,7 @@ void VstConnection<ST>::sendAuthenticationRequest() {
   item->prepareForNetwork(_vstVersion, header, asio_ns::const_buffer(0,0));
 
   auto self = shared_from_this();
-  item->_callback = [this, self](Error error, std::unique_ptr<Request>,
+  item->_callback = [self, this](Error error, std::unique_ptr<Request>,
                                  std::unique_ptr<Response> resp) {
     if (error || resp->statusCode() != StatusOK) {
       _state.store(State::Failed, std::memory_order_release);
@@ -255,7 +274,7 @@ void VstConnection<ST>::sendAuthenticationRequest() {
   
   // actually send auth request
   asio_ns::post(*_io_context, [this, self, item] {
-    auto cb = [this, self, item](asio_ns::error_code const& ec,
+    auto cb = [self, item, this](asio_ns::error_code const& ec,
                                  std::size_t transferred) {
       if (ec) {
         asyncWriteCallback(ec, transferred, std::move(item)); // error handling
@@ -286,7 +305,7 @@ void VstConnection<ST>::startWriting() {
                                                std::memory_order_seq_cst)) {
       FUERTE_LOG_TRACE << "startWriting (vst): starting write\n";
       auto self = shared_from_this(); // only one thread can get here per connection
-      asio_ns::post(*_io_context, [this, self] {
+      asio_ns::post(*_io_context, [self, this] {
         asyncWriteNextRequest();
       });
       return;
@@ -328,7 +347,7 @@ void VstConnection<ST>::asyncWriteNextRequest() {
   setTimeout();             // prepare request / connection timeouts
   
   auto self = shared_from_this();
-  auto cb = [this, self, item](asio_ns::error_code const& ec, std::size_t transferred) {
+  auto cb = [self, item, this](asio_ns::error_code const& ec, std::size_t transferred) {
     asyncWriteCallback(ec, transferred, std::move(item));
   };
   asio_ns::async_write(_protocol.socket, item->_requestBuffers, cb);
@@ -404,7 +423,7 @@ void VstConnection<ST>::startReading() {
   while (!(state & READ_LOOP_ACTIVE)) {
     if (_loopState.compare_exchange_weak(state, state | READ_LOOP_ACTIVE)) {
       auto self = shared_from_this(); // only one thread can get here per connection
-      asio_ns::post(*_io_context, [this, self] {
+      asio_ns::post(*_io_context, [self, this] {
         asyncReadSome();
       });
       return;
@@ -444,7 +463,7 @@ void VstConnection<ST>::asyncReadSome() {
 #endif
   
   auto self = shared_from_this();
-  auto cb = [this, self](asio_ns::error_code const& ec, size_t transferred) {
+  auto cb = [self, this](asio_ns::error_code const& ec, size_t transferred) {
     // received data is "committed" from output sequence to input sequence
     _receiveBuffer.commit(transferred);
     asyncReadCallback(ec, transferred);
@@ -613,11 +632,15 @@ void VstConnection<ST>::setTimeout() {
   }
   
   _timeout.expires_at(expires);
-  auto self = shared_from_this();
-  _timeout.async_wait([this, self](asio_ns::error_code const& ec) {
+  std::weak_ptr<Connection> self = shared_from_this();
+  _timeout.async_wait([self, this](asio_ns::error_code const& ec) {
     if (ec) {  // was canceled
       return;
     }
+    auto s = self.lock();
+    if (!s) {
+      return;
+    }
       
     // cancel expired requests
     auto now = std::chrono::steady_clock::now();
diff --git a/3rdParty/fuerte/src/VstConnection.h b/3rdParty/fuerte/src/VstConnection.h
index ee12abf07d..f5d10e65c5 100644
--- a/3rdParty/fuerte/src/VstConnection.h
+++ b/3rdParty/fuerte/src/VstConnection.h
@@ -72,11 +72,14 @@ class VstConnection final : public Connection {
   /// Activate the connection.
   void startConnection() override final;
   
-  /// called on shutdown, always call superclass
-  void shutdownConnection(const ErrorCondition) override;
+  /// @brief cancel the connection, unusable afterwards
+  void cancel() override final;
 
  private:
   
+  /// shutdown connection, cancel async operations
+  void shutdownConnection(const ErrorCondition);
+  
   void restartConnection(const ErrorCondition);
   
   void finishInitialization();
@@ -151,7 +154,8 @@ class VstConnection final : public Connection {
   static_assert((WRITE_LOOP_ACTIVE & READ_LOOP_ACTIVE) == 0, "");
   
   /// elements to send out
-  boost::lockfree::queue<vst::RequestItem*> _writeQueue;
+  boost::lockfree::queue<vst::RequestItem*,
+    boost::lockfree::capacity<1024>> _writeQueue;
 };
 
 }}}}  // namespace arangodb::fuerte::v1::vst
diff --git a/arangod/GeneralServer/GeneralCommTask.cpp b/arangod/GeneralServer/GeneralCommTask.cpp
index 80e710ee9f..20c23a8bd2 100644
--- a/arangod/GeneralServer/GeneralCommTask.cpp
+++ b/arangod/GeneralServer/GeneralCommTask.cpp
@@ -192,6 +192,7 @@ GeneralCommTask::RequestFlow GeneralCommTask::prepareExecution(
         break; // continue with auth check
       }
       // intentional fallthrough
+      [[gnu::fallthrough]];
     }
     case ServerState::Mode::TRYAGAIN: {
       if (path.find("/_admin/shutdown") == std::string::npos &&
diff --git a/arangosh/Shell/V8ClientConnection.cpp b/arangosh/Shell/V8ClientConnection.cpp
index 2d5789e912..ec11aa047e 100644
--- a/arangosh/Shell/V8ClientConnection.cpp
+++ b/arangosh/Shell/V8ClientConnection.cpp
@@ -62,6 +62,10 @@ V8ClientConnection::V8ClientConnection()
       _vpackOptions(VPackOptions::Defaults) {
   _vpackOptions.buildUnindexedObjects = true;
   _vpackOptions.buildUnindexedArrays = true;
+  _builder.onFailure([this](int error, std::string const& msg) {
+    _lastHttpReturnCode = 503;
+    _lastErrorMessage = msg;
+  });
 }
 
 V8ClientConnection::~V8ClientConnection() {
@@ -69,34 +73,15 @@ V8ClientConnection::~V8ClientConnection() {
   _loop.forceStop();
 }
 
-void V8ClientConnection::init(ClientFeature* client) {
-  _requestTimeout = std::chrono::duration<double>(client->requestTimeout());
-  _username = client->username();
-  _password = client->password();
-  _databaseName = client->databaseName();
-
-  fuerte::ConnectionBuilder builder;
-  builder.endpoint(client->endpoint());
-  if (!client->username().empty()) {
-    builder.user(client->username()).password(client->password());
-    builder.authenticationType(fuerte::AuthenticationType::Basic);
-  } else if (!client->jwtSecret().empty()) {
-    builder.jwtToken(fuerte::jwt::generateInternalToken(client->jwtSecret(), "arangosh"));
-    builder.authenticationType(fuerte::AuthenticationType::Jwt);
-  }
-  builder.onFailure([this](int error, std::string const& msg) {
-    _lastHttpReturnCode = 505;
-    _lastErrorMessage = msg;
-  });
+void V8ClientConnection::createConnection() {
  
-  shutdownConnection(); 
-  _connection = builder.connect(_loop);
+  _connection = _builder.connect(_loop);
   
   fuerte::StringMap params{{"details","true"}};
   auto req = fuerte::createRequest(fuerte::RestVerb::Get, "/_api/version", params);
   req->header.database = _databaseName;
   try {
-    auto res = _connection->sendRequestSync(std::move(req));
+    auto res = _connection->sendRequest(std::move(req));
     _lastHttpReturnCode = res->statusCode();
     
     if (_lastHttpReturnCode == 200) {
@@ -140,19 +125,16 @@ void V8ClientConnection::init(ClientFeature* client) {
     }
   } catch (fuerte::ErrorCondition const& e) { // connection error
     _lastErrorMessage = fuerte::to_string(e);
-    _lastHttpReturnCode = 505;
+    _lastHttpReturnCode = 503;
   }
 }
 
 void V8ClientConnection::setInterrupted(bool interrupted) {
-  if (_connection) {
-    if (interrupted) {
-      shutdownConnection(); 
-    } else {
-      if (_connection->state() == fuerte::Connection::State::Disconnected) {
-        _connection->startConnection();
-      }
-    }
+  if (interrupted && _connection.get() != nullptr) {
+    _connection->cancel();
+    _connection.reset();
+  } else if (!interrupted && _connection.get() == nullptr) {
+    createConnection();
   }
 }
 
@@ -168,12 +150,34 @@ std::string V8ClientConnection::endpointSpecification() const {
 }
 
 void V8ClientConnection::connect(ClientFeature* client) {
-  this->init(client);
+  TRI_ASSERT(client);
+  
+  _requestTimeout = std::chrono::duration<double>(client->requestTimeout());
+  _databaseName = client->databaseName();
+  _builder.endpoint(client->endpoint());
+  if (!client->username().empty()) {
+    _builder.user(client->username()).password(client->password());
+    _builder.authenticationType(fuerte::AuthenticationType::Basic);
+  } else if (!client->jwtSecret().empty()) {
+    _builder.jwtToken(fuerte::jwt::generateInternalToken(client->jwtSecret(), "arangosh"));
+    _builder.authenticationType(fuerte::AuthenticationType::Jwt);
+  }
+  createConnection();
 }
 
 void V8ClientConnection::reconnect(ClientFeature* client) {
+  _requestTimeout = std::chrono::duration<double>(client->requestTimeout());
+  _databaseName = client->databaseName();
+  _builder.endpoint(client->endpoint());
+  if (!client->username().empty()) {
+    _builder.user(client->username()).password(client->password());
+    _builder.authenticationType(fuerte::AuthenticationType::Basic);
+  } else if (!client->jwtSecret().empty()) {
+    _builder.jwtToken(fuerte::jwt::generateInternalToken(client->jwtSecret(), "arangosh"));
+    _builder.authenticationType(fuerte::AuthenticationType::Jwt);
+  }
   try {
-    init(client);
+    createConnection();
   } catch (...) {
     std::string errorMessage = "error in '" + client->endpoint() + "'";
     throw errorMessage;
@@ -186,7 +190,7 @@ void V8ClientConnection::reconnect(ClientFeature* client) {
         << "'" << endpointSpecification() << "', "
         << "version " << _version << " [" << _mode << "], "
         << "database '" << _databaseName << "', "
-        << "username: '" << _username << "'";
+        << "username: '" << client->username() << "'";
   } else {
     if (client->getWarnConnect()) {
       LOG_TOPIC(ERR, arangodb::Logger::FIXME)
@@ -1353,7 +1357,7 @@ v8::Local<v8::Value> V8ClientConnection::requestData(
   _lastHttpReturnCode = 0;
   if (!_connection) {
     _lastErrorMessage = "not connected";
-    _lastHttpReturnCode = 505;
+    _lastHttpReturnCode = 503;
     return v8::Null(isolate);
   }
   
@@ -1403,7 +1407,7 @@ v8::Local<v8::Value> V8ClientConnection::requestData(
   
   std::unique_ptr<fuerte::Response> response;
   try {
-    response = _connection->sendRequestSync(std::move(req));
+    response = _connection->sendRequest(std::move(req));
   } catch (fuerte::ErrorCondition const& ec) {
     return handleResult(isolate, nullptr, ec);
   }
@@ -1455,10 +1459,10 @@ v8::Local<v8::Value> V8ClientConnection::requestDataRaw(
   
   std::unique_ptr<fuerte::Response> response;
   try {
-    response = _connection->sendRequestSync(std::move(req));
+    response = _connection->sendRequest(std::move(req));
   } catch (fuerte::ErrorCondition const& e) {
     _lastErrorMessage.assign(fuerte::to_string(e));
-    _lastHttpReturnCode = 505;
+    _lastHttpReturnCode = 503;
   }
   
   v8::Local<v8::Object> result = v8::Object::New(isolate);
@@ -1756,7 +1760,7 @@ void V8ClientConnection::initServer(v8::Isolate* isolate,
 
 void V8ClientConnection::shutdownConnection() {
   if (_connection) {
-    _connection->shutdownConnection(fuerte::ErrorCondition::Canceled); 
+    _connection->cancel();
     _connection.reset();
   }
 }
diff --git a/arangosh/Shell/V8ClientConnection.h b/arangosh/Shell/V8ClientConnection.h
index 92b4cd3bb5..1acb3c7733 100644
--- a/arangosh/Shell/V8ClientConnection.h
+++ b/arangosh/Shell/V8ClientConnection.h
@@ -28,6 +28,7 @@
 #include "Basics/Common.h"
 #include "Basics/StringRef.h"
 
+#include <fuerte/connection.h>
 #include <fuerte/loop.h>
 #include <fuerte/types.h>
 #include <v8.h>
@@ -58,7 +59,7 @@ class V8ClientConnection {
   ~V8ClientConnection();
 
  public:
-  void setInterrupted(bool value);
+  void setInterrupted(bool interrupted);
   bool isConnected();
   
   void connect(ClientFeature*);
@@ -66,8 +67,8 @@ class V8ClientConnection {
 
   std::string const& databaseName() const { return _databaseName; }
   void setDatabaseName(std::string const& value) { _databaseName = value; }
-  std::string const& username() const { return _username; }
-  std::string const& password() const { return _password; }
+  std::string username() const { return _builder.user(); }
+  std::string password() const { return _builder.password(); }
   int lastHttpReturnCode() const { return _lastHttpReturnCode; }
   std::string lastErrorMessage() const { return _lastErrorMessage; }
   std::string const& version() const { return _version; }
@@ -107,7 +108,8 @@ class V8ClientConnection {
                   ClientFeature*);
   
  private:
-  void init(ClientFeature*);
+  
+  void createConnection();
 
   v8::Local<v8::Value> requestData(
       v8::Isolate* isolate, fuerte::RestVerb verb,
@@ -130,8 +132,6 @@ class V8ClientConnection {
 
  private:
   std::string _databaseName;
-  std::string _username;
-  std::string _password;
   std::chrono::duration<double> _requestTimeout;
   
   int _lastHttpReturnCode;
@@ -140,8 +140,9 @@ class V8ClientConnection {
   std::string _version;
   std::string _mode;
   
-  std::shared_ptr<fuerte::Connection> _connection;
   fuerte::EventLoopService _loop;
+  fuerte::ConnectionBuilder _builder;
+  std::shared_ptr<fuerte::Connection> _connection;
   velocypack::Options _vpackOptions;
 };
 }  // namespace arangodb
diff --git a/arangosh/Shell/V8ShellFeature.cpp b/arangosh/Shell/V8ShellFeature.cpp
index 89de6046b8..dcffda4cc9 100644
--- a/arangosh/Shell/V8ShellFeature.cpp
+++ b/arangosh/Shell/V8ShellFeature.cpp
@@ -282,10 +282,10 @@ bool V8ShellFeature::printHello(V8ClientConnection* v8connection) {
 }
 
 // the result is wrapped in a Javascript variable SYS_ARANGO
-std::unique_ptr<V8ClientConnection> V8ShellFeature::setup(
+std::shared_ptr<V8ClientConnection> V8ShellFeature::setup(
     v8::Local<v8::Context>& context, bool createConnection,
     std::vector<std::string> const& positionals, bool* promptError) {
-  std::unique_ptr<V8ClientConnection> v8connection;
+  std::shared_ptr<V8ClientConnection> v8connection;
 
   ClientFeature* client = nullptr;
 
@@ -293,10 +293,6 @@ std::unique_ptr<V8ClientConnection> V8ShellFeature::setup(
     client = server()->getFeature<ClientFeature>("Client");
 
     if (client != nullptr && client->isEnabled()) {
-      /*auto jwtSecret = client->jwtSecret();
-      if (!jwtSecret.empty()) {
-        V8ClientConnection::setJwtSecret(jwtSecret);
-      }*/
       v8connection = std::make_unique<V8ClientConnection>();
       v8connection->connect(client);
     } else {
@@ -338,7 +334,7 @@ int V8ShellFeature::runShell(std::vector<std::string> const& positionals) {
 
   if (v8connection != nullptr) {
     v8LineEditor.setSignalFunction(
-        [&v8connection]() { v8connection->setInterrupted(true); });
+        [v8connection]() { v8connection->setInterrupted(true); });
   }
 
   v8LineEditor.open(_console->autoComplete());
@@ -435,7 +431,7 @@ int V8ShellFeature::runShell(std::vector<std::string> const& positionals) {
       // this will change the prompt for the next round
       promptError = true;
     }
-
+    
     if (v8connection != nullptr) {
       v8connection->setInterrupted(false);
     }
@@ -910,8 +906,8 @@ void V8ShellFeature::initGlobals() {
   auto ctx = ArangoGlobalContext::CONTEXT;
 
   if (ctx == nullptr) {
-    LOG_TOPIC(ERR, arangodb::Logger::FIXME)
-        << "failed to get global context.  ";
+    LOG_TOPIC(FATAL, arangodb::Logger::FIXME)
+        << "failed to get global context";
     FATAL_ERROR_EXIT();
   }
 
diff --git a/arangosh/Shell/V8ShellFeature.h b/arangosh/Shell/V8ShellFeature.h
index 82921e5766..2cdb77b502 100644
--- a/arangosh/Shell/V8ShellFeature.h
+++ b/arangosh/Shell/V8ShellFeature.h
@@ -76,7 +76,7 @@ class V8ShellFeature final : public application_features::ApplicationFeature {
   void initGlobals();
   void initMode(ShellFeature::RunMode, std::vector<std::string> const&);
   void loadModules(ShellFeature::RunMode);
-  std::unique_ptr<V8ClientConnection> setup(v8::Local<v8::Context>& context, bool,
+  std::shared_ptr<V8ClientConnection> setup(v8::Local<v8::Context>& context, bool,
                                             std::vector<std::string> const&,
                                             bool* promptError = nullptr);
 
@@ -88,4 +88,4 @@ class V8ShellFeature final : public application_features::ApplicationFeature {
 
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/lib/V8/V8LineEditor.cpp b/lib/V8/V8LineEditor.cpp
index 224103a8c9..8c03b43802 100644
--- a/lib/V8/V8LineEditor.cpp
+++ b/lib/V8/V8LineEditor.cpp
@@ -23,6 +23,8 @@
 
 #include "V8LineEditor.h"
 
+#include "Basics/Mutex.h"
+#include "Basics/MutexLocker.h"
 #include "Basics/StringUtils.h"
 #include "Basics/tri-strings.h"
 #include "Logger/Logger.h"
@@ -31,14 +33,17 @@
 #include "V8/v8-utils.h"
 
 using namespace arangodb;
-using namespace arangodb;
+
+namespace {
+static arangodb::Mutex singletonMutex;
+static arangodb::V8LineEditor* singleton = nullptr;
+}
+
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief the active instance of the editor
 ////////////////////////////////////////////////////////////////////////////////
 
-static std::atomic<V8LineEditor*> SINGLETON(nullptr);
-
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief signal handler for CTRL-C
 ////////////////////////////////////////////////////////////////////////////////
@@ -53,7 +58,8 @@ static bool SignalHandler(DWORD eventType) {
     case CTRL_LOGOFF_EVENT:
     case CTRL_SHUTDOWN_EVENT: {
       // get the instance of the console
-      auto instance = SINGLETON.load();
+      MUTEX_LOCKER(mutex, ::singletonMutex);
+      auto instance = ::singleton;
 
       if (instance != nullptr) {
         if (instance->isExecutingCommand()) {
@@ -77,7 +83,8 @@ static bool SignalHandler(DWORD eventType) {
 
 static void SignalHandler(int /*signal*/) {
   // get the instance of the console
-  auto instance = SINGLETON.load();
+  MUTEX_LOCKER(mutex, ::singletonMutex);
+  auto instance = ::singleton;
 
   if (instance != nullptr) {
     if (instance->isExecutingCommand()) {
@@ -375,8 +382,12 @@ V8LineEditor::V8LineEditor(v8::Isolate* isolate,
       _context(context),
       _executingCommand(false) {
   // register global instance
-  TRI_ASSERT(SINGLETON.load() == nullptr);
-  SINGLETON.store(this);
+ 
+  { 
+    MUTEX_LOCKER(mutex, ::singletonMutex);
+    TRI_ASSERT(::singleton == nullptr);
+    ::singleton = this;
+  }
 
   // create shell
   _shell = ShellBase::buildShell(history, new V8Completer());
@@ -409,6 +420,7 @@ V8LineEditor::V8LineEditor(v8::Isolate* isolate,
 
 V8LineEditor::~V8LineEditor() {
   // unregister global instance
-  TRI_ASSERT(SINGLETON.load() != nullptr);
-  SINGLETON.store(nullptr);
+  MUTEX_LOCKER(mutex, ::singletonMutex);
+  TRI_ASSERT(::singleton != nullptr);
+  ::singleton = nullptr;
 }