diff --git a/.ruby-version b/.ruby-version
index 6a81b4c8..bea438e9 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.7.8
+3.3.1
diff --git a/Dockerfile b/Dockerfile
index e3986750..a3152fea 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.7
+FROM ruby:3.3
 
 RUN gem install zold
 EXPOSE 4096