diff --git a/Dockerfile b/Dockerfile
index 2b650b3..d4ff7f4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.7.4-alpine
+FROM ruby:2.7.4-alpine3.12
 
 EXPOSE 4000
 
diff --git a/Gemfile b/Gemfile
index 0b61349..e1adb55 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 source "https://rubygems.org"
 
-ruby "2.7.3"
+ruby "2.7.4"
 
 gemspec