diff --git a/Dockerfile b/Dockerfile
index c320b4f..0bfce1b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:18.04
+FROM ubuntu:20.04
 
 RUN \
   apt update && \
@@ -9,7 +9,7 @@ ENV DEBIAN_FRONTEND noninteractive
 ENV TIMEOUT 12h
 ENV WEB_ROOT /
 ENV MIRROR_URL http://archive.ubuntu.com/ubuntu
-ENV DIST1 bionic
+ENV DIST1 focal
 ENV DIST2 ""
 ENV DIST3 ""
 ENV NTHREADS 10
diff --git a/README.md b/README.md
index a239566..9812f8f 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,8 @@ deb [arch=amd64] http://repo-server:81/ubuntu/mirror/ppa.launchpad.net/jonathonf
   - repeat this for all the repos in EXTRA1..5
 
 ## Changelog
+* 2021-05-12
+  * Updated to Ubuntu focal
 * 2020-01-31
   * support DIST1...3 for different releases