diff --git a/.travis.yml b/.travis.yml
index 22ac973cf6f0..92d481012546 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,6 +16,8 @@ env:
 
 before_install:
  - |
+    # work-around for issue https://github.com/travis-ci/travis-ci/issues/6307
+    # might not be necessary in the future
     if [ "$TRAVIS_OS_NAME" == "osx" ]; then
      command curl -sSL https://rvm.io/mpapis.asc | gpg --import -
      rvm get stable