diff --git a/Dockerfile.multistage b/Dockerfile.multistage
index d504114..d9614a7 100644
--- a/Dockerfile.multistage
+++ b/Dockerfile.multistage
@@ -1,4 +1,4 @@
-FROM ubuntu:focal AS builder
+FROM debian:buster-slim AS builder
 
 # needed to install tzdata
 ARG DEBIAN_FRONTEND=noninteractive