diff --git a/.travis.yml b/.travis.yml
index 26aefaebe..956702401 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -44,11 +44,31 @@ matrix:
         - PYTHON_BUILD=true
         - BREW_BUNDLE=true
 
-    - name: "klayout python3.6.5_1 osx10.13"
+    - name: "klayout python3.6.6 osx10.13"
       os: osx
       osx_image: xcode9.4  # macOS 10.13
       env:
-        - MATRIX_EVAL="brew update; brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/f2a764ef944b1080be64bd88dca9a1d80130c558/Formula/python.rb; brew switch python 3.6.5_1; shopt -s expand_aliases; alias python='python3'; alias pip='pip3';"
+        - MATRIX_EVAL="brew update; brew install sashkab/python/python36; brew link --force --overwrite python36; shopt -s expand_aliases; alias python='/usr/local/opt/python36/bin/python3.6'; alias pip='/usr/local/opt/python36/bin/pip3.6';"
+        - ARCHFLAGS="-std=c++11"
+        - PIP_UPDATE="1"
+        - PYTHON_BUILD=true
+        - BREW_BUNDLE=false
+
+    - name: "klayout python3.5.6 osx10.13"
+      os: osx
+      osx_image: xcode9.4  # macOS 10.13
+      env:
+        - MATRIX_EVAL="brew update; brew install sashkab/python/python35; brew link --force --overwrite python35; shopt -s expand_aliases; alias python='/usr/local/opt/python35/bin/python3.5'; alias pip='/usr/local/opt/python35/bin/pip3.5';"
+        - ARCHFLAGS="-std=c++11"
+        - PIP_UPDATE="1"
+        - PYTHON_BUILD=true
+        - BREW_BUNDLE=false
+
+    - name: "klayout python3.4.9 osx10.13"
+      os: osx
+      osx_image: xcode9.4  # macOS 10.13
+      env:
+        - MATRIX_EVAL="brew update; brew install sashkab/python/python34; brew link --force --overwrite python34; shopt -s expand_aliases; alias python='/usr/local/opt/python34/bin/python3.4'; alias pip='/usr/local/opt/python34/bin/pip3.4';"
         - ARCHFLAGS="-std=c++11"
         - PIP_UPDATE="1"
         - PYTHON_BUILD=true