diff --git a/.travis.yml b/.travis.yml
index 87ea3d2..0252ced 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -152,6 +152,7 @@ matrix:
             - clang-3.4
 
     - os: linux
+      dist: trusty
       compiler: clang++-3.5
       env: TOOLSET=clang COMPILER=clang++-3.5 CXXSTD=03,11,14,1z
       addons:
@@ -321,7 +322,7 @@ matrix:
     - os: linux
       dist: bionic
       compiler: clang++-libc++
-      env: UBSAN=1 TOOLSET=clang COMPILER=clang++-libc++ CXXSTD=03,11,14,17,2a UBSAN_OPTIONS=print_stacktrace=1
+      env: TOOLSET=clang COMPILER=clang++-libc++ CXXSTD=03,11,14,17,2a
       addons:
         apt:
           packages: