diff --git a/tests/_etc/travis/install b/tests/_etc/travis/install
index 9c83978..e443e45 100755
--- a/tests/_etc/travis/install
+++ b/tests/_etc/travis/install
@@ -70,6 +70,7 @@ mv -nv GeoLite2-City.mmdb var/config/
 
 
 ##  install composer dependencies
+rm composer.lock
 
 COMPOSER_MEMORY_LIMIT=-1 composer install --no-scripts