diff --git a/include/pyserial b/include/pyserial
index 8bec5552882..c54c81d933b 160000
--- a/include/pyserial
+++ b/include/pyserial
@@ -1 +1 @@
-Subproject commit 8bec55528827d09937f411e27195ec396993d75c
+Subproject commit c54c81d933b847458d465cd77e96cd702ff2e7be
diff --git a/readme.md b/readme.md
index 47f7bd76fd6..849f66345c0 100644
--- a/readme.md
+++ b/readme.md
@@ -79,7 +79,7 @@ For reference, the following dependencies are included in Git submodules:
 * brlapi Python bindings, version 0.5.7 or later, distributed with [BRLTTY for Windows](http://brl.thefreecat.org/brltty/), version 4.2-2
 * ALVA BC6 generic dll, version 3.0.4.1
 * lilli.dll, version 2.1.0.0
-* [pyserial](http://pypi.python.org/pypi/pyserial), version 2.7
+* [pySerial](http://pypi.python.org/pypi/pyserial), version 3.4
 * [Python interface to FTDI driver/chip](http://fluidmotion.dyndns.org/zenphoto/index.php?p=news&title=Python-interface-to-FTDI-driver-chip)
 * [Py2Exe](http://sourceforge.net/projects/py2exe/), version 0.6.9
 * [Nulsoft Install System](http://nsis.sourceforge.net/), version 2.51
diff --git a/source/braille.py b/source/braille.py
index 85d039909fb..b769cdef667 100644
--- a/source/braille.py
+++ b/source/braille.py
@@ -2119,6 +2119,8 @@ def initialize():
 	global handler
 	config.addConfigDirsToPythonPackagePath(brailleDisplayDrivers)
 	log.info("Using liblouis version %s" % louis.version())
+	import serial
+	log.info("Using pySerial version %s"%serial.VERSION)
 	# #6140: Migrate to new table names as smoothly as possible.
 	oldTableName = config.conf["braille"]["translationTable"]
 	newTableName = brailleTables.RENAMED_TABLES.get(oldTableName)
diff --git a/source/brailleDisplayDrivers/ecoBraille.py b/source/brailleDisplayDrivers/ecoBraille.py
index 7444fbe4394..ae1b88686de 100644
--- a/source/brailleDisplayDrivers/ecoBraille.py
+++ b/source/brailleDisplayDrivers/ecoBraille.py
@@ -171,10 +171,10 @@ def __init__(self, port):
 		# Try to open port
 		self._dev = serial.Serial(self._port, baudrate = 19200,  bytesize = serial.EIGHTBITS, parity = serial.PARITY_NONE, stopbits = serial.STOPBITS_ONE)
 		# Use a longer timeout when waiting for initialisation.
-		self._dev.timeout = self._dev.writeTimeout = 2.7
+		self._dev.timeout = self._dev.write_timeout = 2.7
 		self._ecoType  = eco_in_init(self._dev)
 		# Use a shorter timeout hereafter.
-		self._dev.timeout = self._dev.writeTimeout = TIMEOUT
+		self._dev.timeout = self._dev.write_timeout = TIMEOUT
 		# Always send the protocol answer.
 		self._dev.write("\x61\x10\x02\xf1\x57\x57\x57\x10\x03")
 		self._dev.write("\x10\x02\xbc\x00\x00\x00\x00\x00\x10\x03")
@@ -202,7 +202,7 @@ def display(self, cells):
 			pass
 
 	def _handleResponses(self):
-		if self._dev.inWaiting():
+		if self._dev.in_waiting:
 			command = eco_in(self._dev)
 			if command:
 				try:
diff --git a/source/brailleDisplayDrivers/hedoMobilLine.py b/source/brailleDisplayDrivers/hedoMobilLine.py
index cd3a142b3b6..c4868b67511 100644
--- a/source/brailleDisplayDrivers/hedoMobilLine.py
+++ b/source/brailleDisplayDrivers/hedoMobilLine.py
@@ -100,7 +100,7 @@ def display(self, cells):
 		self._ser.write(line)
 
 	def handleResponses(self, wait=False):
-		while wait or self._ser.inWaiting():
+		while wait or self._ser.in_waiting:
 			data = self._ser.read(1)
 			if data:
 				# do not handle acknowledge bytes
diff --git a/source/brailleDisplayDrivers/hedoProfiLine.py b/source/brailleDisplayDrivers/hedoProfiLine.py
index 5a3b9d18cc7..1669e977f48 100644
--- a/source/brailleDisplayDrivers/hedoProfiLine.py
+++ b/source/brailleDisplayDrivers/hedoProfiLine.py
@@ -124,7 +124,7 @@ def display(self, cells):
 		self._ser.write(line)
 
 	def handleResponses(self, wait=False):
-		while wait or self._ser.inWaiting():
+		while wait or self._ser.in_waiting:
 			data = self._ser.read(1)
 			if data:
 				# do not handle acknowledge bytes
diff --git a/source/brailleDisplayDrivers/papenmeier_serial.py b/source/brailleDisplayDrivers/papenmeier_serial.py
index b396b03a75d..c751893b2e7 100644
--- a/source/brailleDisplayDrivers/papenmeier_serial.py
+++ b/source/brailleDisplayDrivers/papenmeier_serial.py
@@ -47,9 +47,9 @@ def brl_out(offset, data):
 
 def brl_poll(dev):
 	"""read data from braille display, used by keypress handler"""
-	if dev.inWaiting() < 10: return ""
+	if dev.in_waiting < 10: return ""
 	ret = []
-	ret.append(dev.read(dev.inWaiting()))
+	ret.append(dev.read(dev.in_waiting))
 	if ret[0][0] == chr(STX) and ret[0][9] == chr(ETX):
 		return "".join(ret)
 	return ""
diff --git a/source/brailleDisplayDrivers/seika.py b/source/brailleDisplayDrivers/seika.py
index 691ce3d1366..664d89e2026 100644
--- a/source/brailleDisplayDrivers/seika.py
+++ b/source/brailleDisplayDrivers/seika.py
@@ -100,7 +100,7 @@ def display(self, cells):
 		self._ser.write(line)
 
 	def handleResponses(self):
-		if not self._ser.inWaiting():
+		if not self._ser.in_waiting:
 			return
 		chars = [0,0]
 		key = 0
diff --git a/source/hwIo.py b/source/hwIo.py
index db267b2e244..b5e60ad3b70 100644
--- a/source/hwIo.py
+++ b/source/hwIo.py
@@ -175,8 +175,7 @@ def __init__(self, *args, **kwargs):
 		self._origTimeout = self._ser.timeout
 		# We don't want a timeout while we're waiting for data.
 		self._setTimeout(None)
-		self.inWaiting = self._ser.inWaiting
-		super(Serial, self).__init__(self._ser.hComPort, onReceive)
+		super(Serial, self).__init__(self._ser._port_handle, onReceive)
 
 	def read(self, size=1):
 		data = self._ser.read(size)
@@ -205,21 +204,21 @@ def _setTimeout(self, timeout):
 		# #6035: pyserial reconfigures all settings of the port when setting a timeout.
 		# This can cause error 'Cannot configure port, some setting was wrong.'
 		# Therefore, manually set the timeouts using the Win32 API.
-		# Adapted from pyserial 3.1.1.
+		# Adapted from pyserial 3.4.
 		timeouts = COMMTIMEOUTS()
 		if timeout is not None:
 			if timeout == 0:
 				timeouts.ReadIntervalTimeout = win32.MAXDWORD
 			else:
 				timeouts.ReadTotalTimeoutConstant = max(int(timeout * 1000), 1)
-		if timeout != 0 and self._ser._interCharTimeout is not None:
-			timeouts.ReadIntervalTimeout = max(int(self._ser._interCharTimeout * 1000), 1)
-		if self._ser._writeTimeout is not None:
-			if self._ser._writeTimeout == 0:
+		if timeout != 0 and self._ser._inter_byte_timeout is not None:
+			timeouts.ReadIntervalTimeout = max(int(self._ser._inter_byte_timeout * 1000), 1)
+		if self._ser._write_timeout is not None:
+			if self._ser._write_timeout == 0:
 				timeouts.WriteTotalTimeoutConstant = win32.MAXDWORD
 			else:
-				timeouts.WriteTotalTimeoutConstant = max(int(self._ser._writeTimeout * 1000), 1)
-		SetCommTimeouts(self._ser.hComPort, ctypes.byref(timeouts))
+				timeouts.WriteTotalTimeoutConstant = max(int(self._ser._write_timeout * 1000), 1)
+		SetCommTimeouts(self._ser._port_handle, ctypes.byref(timeouts))
 
 class HIDP_CAPS (ctypes.Structure):
 	_fields_ = (