Drop support for EOL Python 3.3
diff --git a/.travis.yml b/.travis.yml
index f41b88f..821469c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,6 @@
 # See: https://github.com/travis-ci/travis-ci/issues/3024
 python:
   - 2.7
-  - 3.3
   - 3.4
   - 3.5
   - "pypy"
diff --git a/README.md b/README.md
index 965c401..86005fb 100644
--- a/README.md
+++ b/README.md
@@ -40,4 +40,4 @@
 Furthermore, in 4.0 the I/O functions will be streamlined to always work with bytes on all
 supported versions of Python.
 
-Version 4.0 will drop support for Python 2.6, and possibly for Python 3.3.
+Version 4.0 will drop support for Python 2.6 and 3.3.
diff --git a/setup.py b/setup.py
index 81302bf..dc237c8 100755
--- a/setup.py
+++ b/setup.py
@@ -35,12 +35,14 @@
               'License :: OSI Approved :: Apache Software License',
               'Operating System :: OS Independent',
               'Programming Language :: Python',
+              '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 :: 3.5',
               'Programming Language :: Python :: 3.6',
+              'Programming Language :: Python :: Implementation :: CPython',
+              'Programming Language :: Python :: Implementation :: PyPy',
               'Topic :: Security :: Cryptography',
           ],
           install_requires=[
diff --git a/speed.sh b/speed.sh
index 73d5935..e06d825 100755
--- a/speed.sh
+++ b/speed.sh
@@ -29,7 +29,6 @@
 python_versions="
     pypy
     python2.7
-    python3.3
     python3.4
     python3.5
 "
diff --git a/tox.ini b/tox.ini
index ae49b27..a449130 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 # Environment changes have to be manually synced with '.travis.yml'.
-envlist = py27,py33,py34,py35,pypy
+envlist = py27,py34,py35,pypy
 
 [pytest]
 addopts = -v --cov rsa --cov-report term-missing