diff --git a/CHANGELOG.md b/CHANGELOG.md
index e7966a6..b5b594c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## 4.0.0-pre.1 (2019-12-15)
+- Bump [`thelounge`][1] to [`4.0.0-pre.1`](https://github.com/thelounge/thelounge/releases/tag/v4.0.0-pre.1).
+
 ## 3.3.0 (2019-10-28)
 - Bump [`thelounge`][1] to [`3.3.0`](https://github.com/thelounge/thelounge/releases/tag/v3.3.0).
 - Upgrade base images to use Node.js 12.
diff --git a/Dockerfile b/Dockerfile
index ce09661..be8e954 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,6 +15,6 @@ CMD ["thelounge", "start"]
 COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
 
 # Install thelounge.
-ARG THELOUNGE_VERSION=3.3.0
+ARG THELOUNGE_VERSION=4.0.0-pre.1
 RUN yarn --non-interactive --frozen-lockfile global add thelounge@${THELOUNGE_VERSION} && \
     yarn --non-interactive cache clean
diff --git a/Makefile b/Makefile
index a599ad5..43496c3 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-THELOUNGE_VERSION?=3.3.0
+THELOUNGE_VERSION?=4.0.0-pre.1
 ORGANISATION?=thelounge
 
 all: main alpine
diff --git a/alpine/Dockerfile b/alpine/Dockerfile
index 870ab89..e611358 100644
--- a/alpine/Dockerfile
+++ b/alpine/Dockerfile
@@ -15,6 +15,6 @@ CMD ["thelounge", "start"]
 COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
 
 # Install thelounge.
-ARG THELOUNGE_VERSION=3.3.0
+ARG THELOUNGE_VERSION=4.0.0-pre.1
 RUN yarn --non-interactive --frozen-lockfile global add thelounge@${THELOUNGE_VERSION} && \
     yarn --non-interactive cache clean