diff --git a/Dockerfile b/Dockerfile
index 68ab5dc..149855a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -25,6 +25,7 @@ RUN curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | g
 # install docker
 # https://docs.docker.com/engine/install/ubuntu/
 # Note we use the bionic version of docker as it's not available for focal
+# https://github.com/docker/for-linux/issues/1035
 RUN curl -fsSL https://download.docker.com/linux/ubuntu/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg \
     && echo "deb [arch=armhf signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu bionic stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null \
     && apt-get update -y && apt-get install -y docker-ce docker-ce-cli containerd.io