diff --git a/.probo.yaml b/.probo.yaml
index 3ca0b78..1847486 100644
--- a/.probo.yaml
+++ b/.probo.yaml
@@ -1,3 +1,4 @@
+image: proboci/ubuntu-16.04-lamp:php7.1-nightly
 steps:
   - name: Update Composer
     command: '/usr/local/bin/composer self-update'