diff --git a/.ruby-version b/.ruby-version
index 4d54dad..c5106e6 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-4.0.2
+4.0.4
diff --git a/Dockerfile b/Dockerfile
index 252cef2..856d9fe 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,7 +3,7 @@
 
 # For a containerized dev environment, see Dev Containers: https://guides.rubyonrails.org/getting_started_with_devcontainer.html
 
-FROM docker.io/library/ruby:4.0.2-slim@sha256:12f002ff598856284c9fd35526712d5431c47d60dd91eb3a00f9e01777c762d5 AS base
+FROM docker.io/library/ruby:4.0.4-slim@sha256:3fc7a33fb84ba3c876ceccafffc4151c6f2cbbb0c4adf9fd4dbe505130988a8a AS base
 
 # Rails app lives here
 WORKDIR /rails
diff --git a/Gemfile.lock b/Gemfile.lock
index 546eab1..2ff7aa7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -367,7 +367,7 @@ DEPENDENCIES
   sqlite3
 
 RUBY VERSION
-   ruby 4.0.2p0
+  ruby 4.0.4
 
 BUNDLED WITH
-   4.0.6
+  4.0.10