diff --git a/.travis.yml b/.travis.yml
index 236192b..b6ebdae 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,14 +1,15 @@
 language: ruby
 rvm:
 - 2.1.0
 - 2.2.0
 - 2.3.0
+- 2.4.0
 env:
   global:
   - secure: A03DrflHssgYH/ekZlQUbp93B2aaFszXiiSQDxv1mm9oabuQuAQn+aGZmp1v1eA8SdSVu2PAeWNAUXFTAkgIbxRFUScsdbMyG2hdDiAie9t581PRdcRgcPWDPAoigj1xTgI9dbBTljlIJXQZ6+DuI3SpajfV8rksxRjqlgE5aec=
   - secure: fcBXclhQt2XL2iXQC6b3WVa6KGiWqboZK6AWFq2u1o53WK3Wz7eeG2OJwYakJvr23h4U2vvsTbMRT8fen6HXnywOHqPm83qQ6YdukoO5ky95s0zNFtVNn8Nj+ulZveb+zb+DlzXwuOUTSaBfgY0bN3XR12lM9b8qLy5UlZNGlNI=
 notifications:
   irc: "chat.freenode.net#kubuntu-ci"
 before_install:
   - sudo apt-get -qq update
   - sudo apt-get install -y gnupg2
diff --git a/lib/requirement_checker.rb b/lib/requirement_checker.rb
index c2ba63c..8efcc85 100644
--- a/lib/requirement_checker.rb
+++ b/lib/requirement_checker.rb
@@ -1,48 +1,53 @@
 class RequirementChecker
-  COMPATIBLE_RUBIES = %w(2.1.0 2.2.0 2.3.0)
+  # NOTE: The versions are restricted upwards because behavior changes in the
+  # language can result in unexpected outcome when using releaseme. i.e.
+  # you may end up with a broken or malformed tar. To prevent this, a change
+  # here must be followed by running `rake test` to pass the entire test suite!
+  # Also see the section on bumping versions in the REAMDE.
+  COMPATIBLE_RUBIES = %w(2.1.0 2.2.0 2.3.0 2.4.0)
   REQUIRED_BINARIES = %w(svn git tar xz msgfmt gpg2)
 
   def initialize
     @ruby_version = RUBY_VERSION
   end
 
   def check
     err = false
     unless ruby_compatible?
       puts "- Ruby #{COMPATIBLE_RUBIES.join(' or ')} required."
       puts "  Currently using: #{@ruby_version}"
       err = true
     end
     missing_binaries.each do |m|
       puts "- Missing binary: #{m}."
       err = true
     end
     fail 'Not all requirements met.' if err
   end
 
   private
 
   def ruby_compatible?
     COMPATIBLE_RUBIES.each do |v|
       return true if compatible?(v)
     end
     false
   end
 
   def missing_binaries
     missing_binaries = []
     REQUIRED_BINARIES.each do |r|
       missing_binaries << missing(r)
     end
     missing_binaries.compact
   end
 
   def compatible?(a)
     Gem::Dependency.new('', "~> #{a}").match?('', @ruby_version)
   end
 
   def missing(bin)
     return bin unless system("type #{bin} > /dev/null 2>&1")
     nil
   end
 end
diff --git a/test/test_requirement_checker.rb b/test/test_requirement_checker.rb
index ddbb7b6..52db9eb 100644
--- a/test/test_requirement_checker.rb
+++ b/test/test_requirement_checker.rb
@@ -1,75 +1,77 @@
 require 'fileutils'
 
 require_relative 'lib/testme'
 
 require_relative '../lib/requirement_checker'
 
 class TestRequirementChecker < Testme
   def assert_ruby_version_compatible(version)
     checker = RequirementChecker.new
     checker.instance_variable_set(:@ruby_version, version)
     assert(checker.send(:ruby_compatible?),
            "Ruby version #{version} NOT compatible but should be")
   end
 
   def assert_ruby_version_not_compatible(version)
     checker = RequirementChecker.new
     checker.instance_variable_set(:@ruby_version, version)
     assert(!checker.send(:ruby_compatible?),
            "Ruby version #{version} compatible but should not be")
     assert_raise { checker.check }
   end
 
   def with_path(path)
     orig_path = ENV.fetch('PATH')
     ENV['PATH'] = path
     yield
   ensure
     ENV['PATH'] = orig_path if orig_path
   end
 
   def test_versions
     compatibles = %w(
       2.1
       2.1.0
       2.1.1
       2.2
       2.2.0
       2.2.1
       2.3
       2.3.1
+      2.4
+      2.4.1
     )
     compatibles.each { |i| assert_ruby_version_compatible(i) }
     incompatibles = %w(
       1.9.0
       2.0
       2.0.99
-      2.4
-      2.4.1
+      2.5
+      2.5.1
     )
     incompatibles.each { |i| assert_ruby_version_not_compatible(i) }
   end
 
   def all_binaries
     RequirementChecker.const_get(:REQUIRED_BINARIES)
   end
 
   def test_missing_binaries
     with_path('') do
       checker = RequirementChecker.new
       missing_binaries = checker.send(:missing_binaries)
       expected_missing_binaries = all_binaries
       assert_equal(expected_missing_binaries, missing_binaries)
       assert_raise { checker.check }
     end
   end
 
   def test_existing_binaries
     FileUtils.touch(all_binaries)
     FileUtils.chmod('+x', all_binaries)
     with_path(Dir.pwd) do
       missing_binaries = RequirementChecker.new.send(:missing_binaries)
       assert_equal([], missing_binaries)
     end
   end
 end