diff --git a/.travis.yml b/.travis.yml
index bf92db94..0b27c832 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,16 @@
 language: php
 php:
-    - '5.4'
-    - '5.5'
     - '5.6'
     - '7.0'
     - '7.1'
     - '7.2'
     - '7.3'
+matrix:
+    include:
+        - php: '5.4'
+          dist: trusty
+        - php: '5.5'
+          dist: trusty
 before_script:
     - git clone --depth=50 https://github.com/ezyang/simpletest.git
     - cp test-settings.travis.php test-settings.php