diff --git a/descriptor-packages/README b/descriptor-packages/README
index 9d3482d..0d99d66 100644
--- a/descriptor-packages/README
+++ b/descriptor-packages/README
@@ -28,6 +28,7 @@
 On Fedora, install using: pip install charm-tools
 On Ubuntu, install using: apt install charm-tools
 For other platforms, check https://jujucharms.com/docs/2.0/tools-charm-tools
+You need also docker
 
 Due to license issues, for the IMS VNFD package, the IMS charm is fetched
 extracted from the respective git repository prior to packaging.  Because of