diff --git a/t/Dockerfile b/t/Dockerfile
index 50bf882..209da00 100644
--- a/t/Dockerfile
+++ b/t/Dockerfile
@@ -1,11 +1,11 @@
-# DOCKER_NAME=sipwise-base-bullseye
-FROM docker.mgm.sipwise.com/sipwise-bullseye:latest
+# DOCKER_NAME=sipwise-base-bookworm
+FROM docker.mgm.sipwise.com/sipwise-bookworm:latest
 
 # Important! Update this no-op ENV variable when this Dockerfile
 # is updated with the current date. It will force refresh of all
 # of the base images and things like `apt-get update` won't be using
 # old cached versions when the Dockerfile is built.
-ENV REFRESHED_AT 2021-05-03
+ENV REFRESHED_AT 2023-06-26
 
 RUN apt-get update && apt-get install --assume-yes libmodule-build-perl libtrycatch-perl libstrictures-perl
 
@@ -20,13 +20,13 @@ WORKDIR /code/
 # (jump to the next section if you don't want to build yourself!):
 #
 # NOTE: run the following command from root folder of git repository:
-# % docker build --tag="sipwise-base-bullseye" -f ./t/Dockerfile .
-# % docker run --rm -i -t -v $(pwd):/code:rw sipwise-base-bullseye:latest bash
+# % docker build --tag="sipwise-base-bookworm" -f ./t/Dockerfile .
+# % docker run --rm -i -t -v $(pwd):/code:rw sipwise-base-bookworm:latest bash
 #
 # Use the existing docker image:
-# % docker pull docker.mgm.sipwise.com/sipwise-base-bullseye
+# % docker pull docker.mgm.sipwise.com/sipwise-base-bookworm
 # NOTE: run the following command from root folder of git repository:
-# % docker run --rm -i -t -v $(pwd):/code:rw docker.mgm.sipwise.com/sipwise-base-bullseye:latest bash
+# % docker run --rm -i -t -v $(pwd):/code:rw docker.mgm.sipwise.com/sipwise-base-bookworm:latest bash
 #
 # Inside docker:
 #   cd /code && ./t/testrunner