diff --git a/Dockerfile b/Dockerfile
index 0cae5dfd..98697986 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -21,9 +21,9 @@
 # your jupyterhub_config.py will be added automatically
 # from your docker directory.
 
-# https://github.com/tianon/docker-brew-ubuntu-core/commit/3c462555392cb188830b7c91e29311b5fad90cfe
-ARG BASE_IMAGE=ubuntu:bionic-20190612@sha256:9b1702dcfe32c873a770a32cfd306dd7fc1c4fd134adfb783db68defc8894b3c
-FROM $BASE_IMAGE
+# https://github.com/tianon/docker-brew-ubuntu-core/commit/d4313e13366d24a97bd178db4450f63e221803f1
+ARG BASE_IMAGE=ubuntu:bionic-20191029@sha256:6e9f67fa63b0323e9a1e587fd71c561ba48a034504fb804fd26fd8800039835d
+FROM $BASE_IMAGE AS builder
 
 USER root
 
@@ -41,7 +41,12 @@ RUN apt-get update \
  && rm -rf /var/lib/apt/lists/*
 
 # copy only what we need to avoid unnecessary rebuilds
-COPY README.md setup.py requirements.txt pyproject.toml package.json /src/jupyterhub/
+COPY package.json \
+     pyproject.toml \
+     README.md \
+     requirements.txt \
+     setup.py \
+     /src/jupyterhub/
 COPY jupyterhub/ /src/jupyterhub/jupyterhub
 COPY share/ /src/jupyterhub/share
 
@@ -83,7 +88,7 @@ RUN npm install -g configurable-http-proxy@^4.2.0 \
  && rm -rf ~/.npm
 
 # install the wheels we built in the first stage
-COPY --from=0 /src/jupyterhub/wheelhouse /tmp/wheelhouse
+COPY --from=builder /src/jupyterhub/wheelhouse /tmp/wheelhouse
 RUN python3 -m pip install --no-cache /tmp/wheelhouse/*
 
 RUN mkdir -p /srv/jupyterhub/