diff --git a/Dockerfile b/Dockerfile
index 05b2c4e..108dd5c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu
+FROM ubuntu:zesty
 MAINTAINER Andrey Arapov <andrey.arapov@nixaid.com>
 
 # To avoid problems with Dialog and curses wizards
diff --git a/docker-compose.yml b/docker-compose.yml
index 46b78cd..70bf271 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -10,3 +10,5 @@ services:
       - /etc/localtime:/etc/localtime:ro
     environment:
       DISPLAY: unix$DISPLAY
+    cap_add:
+      - IPC_LOCK # lock memory to prevent sensitive values from being swapped to disk.