diff --git a/.travis.yml b/.travis.yml
index d99bd4e..f73e332 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,11 @@
 language: cpp
-compiler:
-  - gcc
+dist: trusty
+sudo: false
+
 matrix:
   include:
     # build on ubuntu
     - os: linux
-      sudo: required
       addons:
         apt:
           sources:
@@ -51,10 +51,15 @@ matrix:
       env:
         - MATRIX_EVAL="CC=gcc-7 && CXX=g++-7"
     # build on osx
+    - os: osx
+      osx_image: xcode8
+
     - os: osx
       osx_image: xcode9.1
+
 before_install:
     - eval "${MATRIX_EVAL}"
+
 script:
   - mkdir build
   - cd build