diff --git a/.drone.yml b/.drone.yml
index f928f8b..533f76c 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -6,7 +6,7 @@ steps:
   - name: build cpp-ubuntu
     image: docker
     commands:
-      - docker build -t erki/cpp-ubuntu:latest - < cpp-ubuntu.Dockerfile
+      - docker build --no-cache -t erki/cpp-ubuntu:latest - < cpp-ubuntu.Dockerfile
     volumes:
       - name: docker_socket
         path: /var/run/docker.sock
@@ -14,7 +14,7 @@ steps:
   - name: build jenkins-ubuntu
     image: docker
     commands:
-      - docker build -t erki/jenkins-ubuntu:latest - < jenkins-ubuntu.Dockerfile
+      - docker build --no-cache -t erki/jenkins-ubuntu:latest - < jenkins-ubuntu.Dockerfile
     volumes:
       - name: docker_socket
         path: /var/run/docker.sock
diff --git a/jenkins-ubuntu.Dockerfile b/jenkins-ubuntu.Dockerfile
index 5711b88..6d9c505 100644
--- a/jenkins-ubuntu.Dockerfile
+++ b/jenkins-ubuntu.Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:focal
 
 ENV DEBIAN_FRONTEND noninteractive