diff --git a/Dockerfile b/Dockerfile
index 5553ec1..64cdefa 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -33,9 +33,10 @@ RUN gem install --no-document bundler
 ENV RAILS_ENV production
 ENV NODE_ENV production
 
-ARG VERSION=4.2.13
+# renovate: datasource=github-releases depName=tootsuite/mastodon versioning=semver extractVersion=^v(?<version>.+)$
+ARG MASTODON_VERSION=4.2.13
 
-RUN curl -L https://github.com/tootsuite/mastodon/archive/v${VERSION}.tar.gz | tar -xz --strip-components 1 -f - && \
+RUN curl -L https://github.com/tootsuite/mastodon/archive/v${MASTODON_VERSION}.tar.gz | tar -xz --strip-components 1 -f - && \
     bundle config --local set deployment 'true' && \
     bundle config --local set without 'development test' && \
     bundle config --local set silence_root_warning true && \