diff --git a/.travis.yml b/.travis.yml
index 567ed5b..8698054 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,15 +15,16 @@ addons:
 env:
   global:
   - NJOBS=1
-  - COMPILER="system"
 
   # Main test targets
   # get versions from: https://opam.ocaml.org/packages/coq/
   # Only use versions that CompCert can build with...
   matrix:
-  - TEST_TARGET="8.6.1"
+  - COMPILER="4.05.0"
+    TEST_TARGET="8.6.1"
   - TEST_TARGET="8.7.2"
   - TEST_TARGET="8.8.1"
+  - TEST_TARGET="8.9.0"
 
 before_script:
   - ./ci/keep_alive.sh &