diff --git a/.ruby-version b/.ruby-version
index 197c4d5..005119b 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.4.0
+2.4.1
diff --git a/.travis.yml b/.travis.yml
index b495b08..049e793 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,6 @@ cache: bundler
 bundler_args: --without yard pry
 sudo: false
 rvm:
-  - 2.1.10
   - 2.2.7
   - 2.3.4
   - 2.4.1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2343227..4b261b9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ Unitwise uses semantic versioning.
 
 ## Unreleased
 
+### Removed
+
+- Support for MRI 2.1
+
 ## 2.1.0 - 2017-04-28
 
 ### Removed
diff --git a/Gemfile b/Gemfile
index 9e37d3d..b121468 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,10 +1,6 @@
 source 'https://rubygems.org'
 
 gem 'coveralls',  '~> 0.7'
-if RUBY_VERSION >= '2.2.0'
-  gem 'bigdecimal', '>= 1.2.6', :platform => :mri
-else
-  gem 'bigdecimal', '<= 1.2.5', :platform => :mri
-end
+gem 'bigdecimal', '>= 1.2.6', :platform => :mri
 
 gemspec
diff --git a/README.md b/README.md
index db64821..2660051 100644
--- a/README.md
+++ b/README.md
@@ -273,7 +273,6 @@ Unitwise(1, "🥃").to_cup
 This library aims to support and is tested against the following Ruby
 implementations:
 
-* Ruby 2.1
 * Ruby 2.2
 * Ruby 2.3
 * Ruby 2.4