diff --git a/travis/altis.yml b/travis/altis.yml
index 4a6f422..b9ee273 100644
--- a/travis/altis.yml
+++ b/travis/altis.yml
@@ -31,6 +31,10 @@ matrix:
   include:
     - php: 7.2
 
+# Ensure composer v1 is still used.
+before_install:
+  - composer self-update --1
+
 # Install application and start the local server
 before_script:
   - composer install