diff --git a/.flake8 b/.flake8
index 2413bf098..a011f30b4 100644
--- a/.flake8
+++ b/.flake8
@@ -12,10 +12,9 @@
 # Nice-to-haves ignored for now
 #   152 E128 continuation line under-indented for visual indent
 #    43 E127 continuation line over-indented for visual indent
-#     6 E999 invalid syntax - FIXME: re-enable after flake8 is running from Python 3.6
 
 [flake8]
-ignore = F401, F811, E127, E128, E301, E302, E305, E501, E701, E704, E999, B303
+ignore = F401, F811, E127, E128, E301, E302, E305, E501, E701, E704, B303
 # We are checking with Python 3 but many of the stubs are Python 2 stubs.
 # A nice future improvement would be to provide separate .flake8
 # configurations for Python 2 and Python 3 files.
diff --git a/.travis.yml b/.travis.yml
index 239c3870a..fd5905316 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,7 @@ language: python
 
 matrix:
   include:
-    - python: "3.5"
+    - python: "3.6-dev"
       env: TEST_CMD="flake8"
     - python: "3.5"
       env: TEST_CMD="./tests/mypy_test.py"
@@ -12,7 +12,8 @@ matrix:
 
 install:
   # pytype needs py-2.7, mypy needs py-3.2+. Additional logic in runtests.py
-  - if [[ $TRAVIS_PYTHON_VERSION == '3.5' ]]; then pip install -U git+git://github.com/python/mypy git+git://github.com/dropbox/typed_ast flake8==3.2.1 flake8-bugbear>=16.12.2 flake8-pyi>=16.12.1; fi
+  - if [[ $TRAVIS_PYTHON_VERSION == '3.6-dev' ]]; then pip install -U flake8==3.2.1 flake8-bugbear>=16.12.2 flake8-pyi>=16.12.2; fi
+  - if [[ $TRAVIS_PYTHON_VERSION == '3.5' ]]; then pip install -U git+git://github.com/python/mypy git+git://github.com/dropbox/typed_ast; fi
   - if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then pip install -U git+git://github.com/google/pytype; fi
 
 script:
diff --git a/requirements-tests-py3.txt b/requirements-tests-py3.txt
index e6ffb9113..bc6189aa9 100644
--- a/requirements-tests-py3.txt
+++ b/requirements-tests-py3.txt
@@ -2,4 +2,4 @@ mypy-lang>=0.4.6
 typed-ast>=0.6.1
 flake8==3.2.1
 flake8-bugbear>=16.12.2
-flake8-pyi>=16.12.1
+flake8-pyi>=16.12.2