diff --git a/Dockerfile b/Dockerfile
index 37599abf..56be9d76 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.4.1
+FROM ruby:2.5.3
 
 ADD Gemfile /app/
 ADD Gemfile.lock /app/
diff --git a/Gemfile b/Gemfile
index 103e2abf..869bce30 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-ruby '2.7.2'
+ruby '2.5.3'
 
 gem 'sinatra'
 gem 'sinatra-flash'
diff --git a/Gemfile.lock b/Gemfile.lock
index 7121cd64..feb0ca70 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -118,7 +118,7 @@ DEPENDENCIES
   zurb-foundation
 
 RUBY VERSION
-   ruby 2.7.2
+   ruby 2.5.3
 
 BUNDLED WITH
    1.17.3