diff --git a/contrib/zmq/zmq_sub.py b/contrib/zmq/zmq_sub.py
--- a/contrib/zmq/zmq_sub.py
+++ b/contrib/zmq/zmq_sub.py
@@ -1,43 +1,87 @@
-#!/usr/bin/env python2
-# Copyright (c) 2014-2016 The Bitcoin Core developers
+#!/usr/bin/env python3
+# Copyright (c) 2014-2017 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+"""
+    ZMQ example using python3's asyncio
+
+    Bitcoin should be started with the command line arguments:
+        bitcoind -testnet -daemon \
+                -zmqpubrawtx=tcp://127.0.0.1:28332 \
+                -zmqpubrawblock=tcp://127.0.0.1:28332 \
+                -zmqpubhashtx=tcp://127.0.0.1:28332 \
+                -zmqpubhashblock=tcp://127.0.0.1:28332
+
+    We use the asyncio library here.  `self.handle()` installs itself as a
+    future at the end of the function.  Since it never returns with the event
+    loop having an empty stack of futures, this creates an infinite loop.  An
+    alternative is to wrap the contents of `handle` inside `while True`.
+
+    A blocking example using python 2.7 can be obtained from the git history:
+    https://github.com/bitcoin/bitcoin/blob/37a7fe9e440b83e2364d5498931253937abe9294/contrib/zmq/zmq_sub.py
+"""
+
 import binascii
+import asyncio
 import zmq
+import zmq.asyncio
+import signal
 import struct
+import sys
+
+if not (sys.version_info.major >= 3 and sys.version_info.minor >= 5):
+    print("This example only works with Python 3.5 and greater")
+    sys.exit(1)
 
 port = 28332
+ip = "172.31.9.161"
+
 
-zmqContext = zmq.Context()
-zmqSubSocket = zmqContext.socket(zmq.SUB)
-zmqSubSocket.setsockopt(zmq.SUBSCRIBE, "hashblock")
-zmqSubSocket.setsockopt(zmq.SUBSCRIBE, "hashtx")
-zmqSubSocket.setsockopt(zmq.SUBSCRIBE, "rawblock")
-zmqSubSocket.setsockopt(zmq.SUBSCRIBE, "rawtx")
-zmqSubSocket.connect("tcp://127.0.0.1:%i" % port)
-
-try:
-    while True:
-        msg = zmqSubSocket.recv_multipart()
-        topic = str(msg[0])
+class ZMQHandler():
+    def __init__(self):
+        self.loop = asyncio.get_event_loop()
+        self.zmqContext = zmq.asyncio.Context()
+
+        self.zmqSubSocket = self.zmqContext.socket(zmq.SUB)
+        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "hashblock")
+        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "hashtx")
+        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "rawblock")
+        self.zmqSubSocket.setsockopt_string(zmq.SUBSCRIBE, "rawtx")
+        self.zmqSubSocket.connect(f"tcp://{ip}:{port}")
+
+    async def handle(self):
+        msg = await self.zmqSubSocket.recv_multipart()
+        topic = msg[0]
         body = msg[1]
         sequence = "Unknown"
         if len(msg[-1]) == 4:
             msgSequence = struct.unpack('<I', msg[-1])[-1]
             sequence = str(msgSequence)
-        if topic == "hashblock":
-            print '- HASH BLOCK (' + sequence + ') -'
-            print binascii.hexlify(body)
-        elif topic == "hashtx":
-            print '- HASH TX  (' + sequence + ') -'
-            print binascii.hexlify(body)
-        elif topic == "rawblock":
-            print '- RAW BLOCK HEADER (' + sequence + ') -'
-            print binascii.hexlify(body[:80])
-        elif topic == "rawtx":
-            print '- RAW TX (' + sequence + ') -'
-            print binascii.hexlify(body)
-
-except KeyboardInterrupt:
-    zmqContext.destroy()
+        if topic == b"hashblock":
+            print(f'- HASH BLOCK ({sequence}) -')
+            print(binascii.hexlify(body))
+        elif topic == b"hashtx":
+            print(f'- HASH TX  ({sequence}) -')
+            print(binascii.hexlify(body))
+        elif topic == b"rawblock":
+            print(f'- RAW BLOCK HEADER ({sequence}) -')
+            print(binascii.hexlify(body[:80]))
+        elif topic == b"rawtx":
+            print(f'- RAW TX ({sequence}) -')
+            print(binascii.hexlify(body))
+        # schedule ourselves to receive the next message
+        asyncio.ensure_future(self.handle())
+
+    def start(self):
+        self.loop.add_signal_handler(signal.SIGINT, self.stop)
+        self.loop.create_task(self.handle())
+        self.loop.run_forever()
+
+    def stop(self):
+        self.loop.stop()
+        self.zmqContext.destroy()
+
+
+daemon = ZMQHandler()
+daemon.start()
diff --git a/contrib/zmq/zmq_sub.py b/contrib/zmq/zmq_sub27.py
copy from contrib/zmq/zmq_sub.py
copy to contrib/zmq/zmq_sub27.py
diff --git a/doc/build-unix.md b/doc/build-unix.md
--- a/doc/build-unix.md
+++ b/doc/build-unix.md
@@ -200,12 +200,7 @@
 
 Boost
 -----
-If you need to build Boost yourself:
-
-	sudo su
-	./bootstrap.sh
-	./bjam install
-
+For documentation on building Boost look at their official documentation: http://www.boost.org/build/doc/html/bbv2/installation.html
 
 Security
 --------