diff --git a/Dockerfile b/Dockerfile
index ef12e99..9df145b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,7 @@
 FROM docker.io/library/alpine:3.11.2
 
 RUN echo "http://dl-3.alpinelinux.org/alpine/edge/testing/" >> /etc/apk/repositories
+RUN apk upgrade
 RUN apk add --update perl perl-lockfile-simple perl-dbi perl-dbd-pg perl-dbd-mysql fetchmail
 RUN mkdir --parents /run/fetchmail