diff --git a/.travis.yml b/.travis.yml
index be35c6d..d082a71 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -24,6 +24,14 @@ env:
   - DB=mysqli MOODLE_BRANCH=MOODLE_31_STABLE
   - DB=mysqli MOODLE_BRANCH=master
 
+matrix:
+  exclude:
+  # Moodle 32 (master) requires at least PHP 5.6.5
+  - php: 5.5
+    env: DB=pgsql MOODLE_BRANCH=master
+  - php: 5.5
+    env: DB=mysqli MOODLE_BRANCH=master
+
 before_install:
   - phpenv config-rm xdebug.ini
   - cd ../..