diff --git a/.travis.yml b/.travis.yml
index 0332bbb..dd4eeed 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,9 @@
 language: python
+dist: xenial
 python:
-  - '2.7'
-  - '3.3'
-  - '3.4'
-  - pypy
+  - 3.5
+  - 3.6
+  - 3.7
 install:
   - pip install -e .
   - pip install -r test-requirements.txt
@@ -18,6 +18,6 @@ deploy:
     secure: qzSC7nsNS1rnDKgiZe2GiojMznf35GLzUeqlf5HESYiKDIlXLIpdxS1Ii9G+afnJH1cGT9dheDUvlRzwZ3eDsZHbVYjKtj/uvy8j4x8H+N66Zvm1AMdGvF4sDCUo01DdbsSe7Xh77VY3kV0AgHb8UZuXOgXcdN0kYJjfWuUWTl0=
   distributions: "sdist bdist_wheel"
   on:
-    python: 2.7
+    python: 3.6
     tags: true
     all_branches: true
diff --git a/HISTORY.rst b/HISTORY.rst
index 1a621c3..f37329e 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -1,6 +1,12 @@
 Version History
 ---------------
 
+`2.0.0`_ (26-Nov-2018)
+~~~~~~~~~~~~~~~~~~~~~~
+- Drop support for Python 2.7, 3.3, 3.4
+- Drop support for Tornado < 4.2
+- Add support for Tornado 5.1 and async with ``AsyncIOHandlerMixin``
+
 `1.0.2`_ (20-Jun-2016)
 ~~~~~~~~~~~~~~~~~~~~~~
 - Add support for async prepare in superclasses of ``HandlerMixin``
@@ -9,6 +15,6 @@ Version History
 ~~~~~~~~~~~~~~~~~~~~~~
  - Adds ``sprockets.mixins.correlation.HandlerMixin``
 
-
+.. _`2.0.0`: https://github.com/sprockets/sprockets.mixins.correlation/compare/1.0.2...2.0.0
 .. _`1.0.2`: https://github.com/sprockets/sprockets.mixins.correlation/compare/1.0.1...1.0.2
 .. _`1.0.1`: https://github.com/sprockets/sprockets.mixins.correlation/compare/0.0.0...1.0.1
diff --git a/LICENSE b/LICENSE
index 3c72859..4fa05e6 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2015 AWeber Communications
+Copyright (c) 2015-2018 AWeber Communications
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 4e8c0ae..8870054 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,6 +1,5 @@
 -r requirements.txt
 -r test-requirements.txt
-flake8>=2.1,<3
+flake8
 sphinx>=1.2,<2
 sphinx-rtd-theme>=0.1,<1.0
-tornado>=4.0,<5
diff --git a/docs/index.rst b/docs/index.rst
index 30bedc7..0d0efc5 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -8,6 +8,10 @@ correlation.HandlerMixin
 .. autoclass:: sprockets.mixins.correlation.HandlerMixin
    :members:
 
+.. autoclass:: sprockets.mixins.correlation.AsyncIOHandlerMixin
+   :members:
+
+
 Contributing to this Library
 ----------------------------
 
diff --git a/requirements.txt b/requirements.txt
index 3f55f96..b33c704 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-tornado>=3.1,<4.4
+tornado>=4.0,<5.2
diff --git a/setup.py b/setup.py
index 27435c0..c9c7f31 100755
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 import codecs
+from os import path
 import sys
 
 import setuptools
@@ -7,24 +8,23 @@ import setuptools
 from sprockets.mixins import correlation
 
 
-def read_requirements_file(req_name):
+def read_requirements(name):
     requirements = []
     try:
-        with codecs.open(req_name, encoding='utf-8') as req_file:
-            for req_line in req_file:
-                if '#' in req_line:
-                    req_line = req_line[0:req_line.find('#')].strip()
-                if req_line:
-                    requirements.append(req_line.strip())
+        with open(path.join('requires', name)) as req_file:
+            for line in req_file:
+                if '#' in line:
+                    line = line[:line.index('#')]
+                line = line.strip()
+                if line.startswith('-r'):
+                    requirements.extend(read_requirements(line[2:].strip()))
+                elif line and not line.startswith('-'):
+                    requirements.append(line)
     except IOError:
         pass
     return requirements
 
 
-install_requires = read_requirements_file('requirements.txt')
-setup_requires = read_requirements_file('setup-requirements.txt')
-tests_require = read_requirements_file('test-requirements.txt')
-
 setuptools.setup(
     name='sprockets.mixins.correlation',
     version=correlation.__version__,
@@ -35,16 +35,15 @@ setuptools.setup(
     author_email='api@aweber.com',
     license=codecs.open('LICENSE', encoding='utf-8').read(),
     classifiers=[
-        'Development Status :: 4 - Beta',
+        'Development Status :: 5 - Production/Stable',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: BSD License',
         'Natural Language :: English',
         'Operating System :: OS Independent',
-        'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.3',
-        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Software Development :: Libraries',
@@ -52,9 +51,8 @@ setuptools.setup(
     ],
     packages=setuptools.find_packages(),
     namespace_packages=['sprockets'],
-    install_requires=install_requires,
-    setup_requires=setup_requires,
-    tests_require=tests_require,
+    install_requires=read_requirements('requirements.txt'),
+    tests_require=read_requirements('test-requirements.txt'),
     test_suite='nose.collector',
     zip_safe=True,
 )
diff --git a/sprockets/mixins/correlation/__init__.py b/sprockets/mixins/correlation/__init__.py
index 0dfe0ff..1611839 100644
--- a/sprockets/mixins/correlation/__init__.py
+++ b/sprockets/mixins/correlation/__init__.py
@@ -1,12 +1,11 @@
 try:
     from .mixins import HandlerMixin
-
-except ImportError as error:
+except ImportError:
 
     class HandlerMixin(object):
         def __init__(self, *args, **kwargs):
-            raise error
+            raise ImportError
 
 
-version_info = (1, 0, 2)
+version_info = (2, 0, 0)
 __version__ = '.'.join(str(v) for v in version_info[:3])
diff --git a/sprockets/mixins/correlation/mixins.py b/sprockets/mixins/correlation/mixins.py
index 121c4d6..7703ec6 100644
--- a/sprockets/mixins/correlation/mixins.py
+++ b/sprockets/mixins/correlation/mixins.py
@@ -1,15 +1,6 @@
 import uuid
 
-import tornado.gen
-import tornado.log
-
-if tornado.version_info[0] >= 4:
-    from tornado.concurrent import is_future
-else:
-    import tornado.concurrent
-
-    def is_future(maybe_future):
-        return isinstance(maybe_future, tornado.concurrent.Future)
+from tornado import concurrent, log
 
 
 class HandlerMixin(object):
@@ -50,14 +41,13 @@ class HandlerMixin(object):
         self.__correlation_id = str(uuid.uuid4())
         super(HandlerMixin, self).__init__(*args, **kwargs)
 
-    @tornado.gen.coroutine
-    def prepare(self):
+    async def prepare(self):
         # Here we want to copy an incoming Correlation-ID header if
         # one exists.  We also want to set it in the outgoing response
         # which the property setter does for us.
         maybe_future = super(HandlerMixin, self).prepare()
-        if is_future(maybe_future):
-            yield maybe_future
+        if concurrent.is_future(maybe_future):
+            await maybe_future
 
         correlation_id = self.get_request_header(self.__header_name, None)
         if correlation_id is not None:
@@ -113,11 +103,11 @@ def correlation_id_logger(handler):
         is processing the client request.
     """
     if handler.get_status() < 400:
-        log_method = tornado.log.access_log.info
+        log_method = log.access_log.info
     elif handler.get_status() < 500:
-        log_method = tornado.log.access_log.warning
+        log_method = log.access_log.warning
     else:
-        log_method = tornado.log.access_log.error
+        log_method = log.access_log.error
     request_time = 1000.0 * handler.request.request_time()
     correlation_id = getattr(handler, "correlation_id", None)
     if correlation_id is None:
diff --git a/test-requirements.txt b/test-requirements.txt
index dc209eb..27a5c8e 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,4 +1,4 @@
-coverage>=3.7,<4
-coveralls>=0.4,<1
-nose>=1.3,<2
-tox>=1.7,<2
+coverage>=4.5.2,<5
+coveralls>=1.5.1,<2
+nose>=1.3.7,<2
+tox>=3.5.3,<4
diff --git a/tests.py b/tests.py
index 9abe799..72ac07f 100644
--- a/tests.py
+++ b/tests.py
@@ -23,18 +23,15 @@ class CorrelationMixinTests(testing.AsyncHTTPTestCase):
         ])
 
     def test_that_correlation_id_is_returned_when_successful(self):
-        self.http_client.fetch(self.get_url('/status/200'), self.stop)
-        response = self.wait()
+        response = self.fetch('/status/200')
         self.assertIsNotNone(response.headers.get('Correlation-ID'))
 
     def test_that_correlation_id_is_returned_in_error(self):
-        self.http_client.fetch(self.get_url('/status/500'), self.stop)
-        response = self.wait()
+        response = self.fetch('/status/500')
         self.assertIsNotNone(response.headers.get('Correlation-ID'))
 
     def test_that_correlation_id_is_copied_from_request(self):
         correlation_id = uuid.uuid4().hex
-        self.http_client.fetch(self.get_url('/status/200'), self.stop,
-                               headers={'Correlation-Id': correlation_id})
-        response = self.wait()
+        response = self.fetch('/status/500',
+                              headers={'Correlation-Id': correlation_id})
         self.assertEqual(response.headers['correlation-id'], correlation_id)
diff --git a/tox.ini b/tox.ini
index 1f3b989..cba03ff 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,py33,py34,pypy,pypy3,tornado31,tornado32,tornado40,tornado43
+envlist = py35,py36,py37,tornado43,torando51
 toxworkdir = {toxinidir}/build/tox
 skip_missing_intepreters = true
 
@@ -9,27 +9,12 @@ deps =
 	tornado
 commands = {envbindir}/nosetests
 
-[testenv:py27]
-deps =
-	{[testenv]deps}
-	mock
-
-[testenv:tornado31]
-deps =
-	-rtest-requirements.txt
-	tornado>=3.1,<3.2
-
-[testenv:tornado32]
-deps =
-	-rtest-requirements.txt
-	tornado>=3.2,<3.3
-
-[testenv:tornado40]
-deps =
-	-rtest-requirements.txt
-	tornado>=4.0,<4.1
-
 [testenv:tornado43]
 deps =
 	-rtest-requirements.txt
 	tornado>=4.3,<4.4
+
+[testenv:tornado51]
+deps =
+	-rtest-requirements.txt
+	tornado>=5.1,<5.2