diff --git a/.ruby-version b/.ruby-version
index 197c4d5c..73462a5a 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.4.0
+2.5.1
diff --git a/Dockerfile b/Dockerfile
index b481c8f4..b424f068 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.4
+FROM ruby:2.5.1
 
 RUN apt-get update \
   && apt-get install -y \