diff --git a/.ruby-version b/.ruby-version
index 86fb65044..d13e837c8 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.3.7
+4.0.6
diff --git a/Dockerfile b/Dockerfile
index 550f547bf..6912e6ba4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:3.3.7-slim@sha256:696f37b3cd55288b5127850e3eeae67dd20595ab77a6724f7bb05baa8c6b4878
+FROM ruby:4.0.6-slim@sha256:607bf92fa7ecebb4a0c6654b62cb44c48d94b36b6f5a754611ddbbe3dc5b6135
 
 # Define args that can be supplied with
 # `docker build --build-args RAILS_ENV=<env>`, defaults to production.