diff --git a/.tool-versions b/.tool-versions
index 97c86d6..6e03b21 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1 +1 @@
-ruby 4.0.0
+ruby 4.0.1
diff --git a/Dockerfile b/Dockerfile
index 3857054..72efa38 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,7 +8,7 @@
 # For a containerized dev environment, see Dev Containers: https://guides.rubyonrails.org/getting_started_with_devcontainer.html
 
 # Make sure RUBY_VERSION matches the Ruby version in .tool-versions
-ARG RUBY_VERSION=3.4.5
+ARG RUBY_VERSION=4.0.1
 FROM docker.io/library/ruby:$RUBY_VERSION-slim AS base
 
 # Rails app lives here