diff --git a/.travis.yml b/.travis.yml
index 038f9873..eae103bf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -96,10 +96,10 @@ matrix:
 #      os: osx
     - env: PAGMO_PLUGINS_NONFREE_BUILD="OSXPython37"
       os: osx
-      osx_image: xcode11
+      osx_image: xcode6.4
     - env: PAGMO_PLUGINS_NONFREE_BUILD="OSXPython27"
       os: osx
-      osx_image: xcode11
+      osx_image: xcode6.4
 script:
 - mkdir build
 - cd build