diff --git a/.appveyor.yml b/.appveyor.yml
index 10d8a6ca5..bf5afb21a 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -3,23 +3,24 @@ environment:
 
     # For Python versions available on Appveyor, see
     # http://www.appveyor.com/docs/installed-software#python
+    # Python 3.0-3.3 have reached EOL
 
     - PYTHON: "C:\\Python27"
     - PYTHON: "C:\\Python34"
     - PYTHON: "C:\\Python35"
     - PYTHON: "C:\\Python36"
+    - PYTHON: "C:\\Python37"
     - PYTHON: "C:\\Python27-x64"
     - PYTHON: "C:\\Python34-x64"
     - PYTHON: "C:\\Python35-x64"
     - PYTHON: "C:\\Python36-x64"
-
-    # Python 3.3 has reached EOL
+    - PYTHON: "C:\\Python37-x64"
 
 install:
   # Prepend Python installation to PATH
   - set PATH=%PYTHON_INSTALL%;%PATH%
 
-  # Prepend Python scripts to PATH (e.g. py.test)
+  # Prepend Python scripts to PATH (e.g. pytest)
   - set PATH=%PYTHON_INSTALL%\\Scripts;%PATH%
 
   # We need to install the python-can library itself
diff --git a/.travis.yml b/.travis.yml
index 24dcef768..9ba990ee8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,17 +1,16 @@
 language: python
 
 python:
-  # CPython:
+  # CPython; versions 3.0-3.3 have reached EOL
   - "2.7"
-  # Python 3.3 has reached EOL and pytest fails there
   - "3.4"
   - "3.5"
   - "3.6"
   - "3.7-dev" # TODO: change to "3.7" once it is supported by travis-ci
   - "nightly"
   # PyPy:
-  - "pypy"
-  - "pypy3.5"
+  - "pypy" # Python 2.7
+  - "pypy3.5" # Python 3.5
 
 os:
   - linux   # Linux is officially supported and we test the library under
@@ -31,16 +30,18 @@ matrix:
   # see "os: ..." above
   include:
     - os: osx
+      osx_image: xcode8.3
       python: "3.6-dev"
     - os: osx
+      osx_image: xcode8.3
       python: "3.7-dev"
     - os: osx
+      osx_image: xcode8.3
       python: "nightly"
 
   allow_failures:
     # allow all nighly builds to fail, since these python versions might be unstable
     - python: "nightly"
-
     # we do not allow dev builds to fail, since these builds are considered stable enough
 
 install:
@@ -53,4 +54,5 @@ script:
   - codecov
   # Build Docs with Sphinx
   # -a Write all files
+  # -n nitpicky
   - if [[ "$TRAVIS_PYTHON_VERSION" == "3.6" ]]; then python -m sphinx -an doc build; fi