diff --git a/.travis.yml b/.travis.yml
index 773bde8..286df03 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -118,6 +118,7 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
+      dist: trusty
       compiler: g++-7
       env: TOOLSET=gcc COMPILER=g++-7 CXXSTD=c++11
       addons: