diff --git a/.travis.yml b/.travis.yml
index 75deb75..c8b09ff 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,7 @@
 language: php
 sudo: false
+# only needed for PHP 5.5 support as of 2019-07
+dist: trusty
 php:
   - '5.5'
   - '5.6'