diff --git a/vars/ubuntu-18.yml b/vars/ubuntu-18.yml
index c05df9cf8..17068759e 100644
--- a/vars/ubuntu-18.yml
+++ b/vars/ubuntu-18.yml
@@ -21,3 +21,6 @@ php_version: 7.2
 # "postgresql_version: 10.3" fails (too detailed for /etc/systemd/system/postgresql-iiab.service on Ubuntu 18.04)
 postgresql_version: 10
 systemd_location: /lib/systemd/system
+# To upgrade U18's Calibre 3.21 to something much better:
+calibre_via_debs: False
+calibre_via_python: True