diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@
 - 2.1.0
 - 2.2.0
 - 2.3.0
+- 2.4.0
 env:
   global:
   - secure: A03DrflHssgYH/ekZlQUbp93B2aaFszXiiSQDxv1mm9oabuQuAQn+aGZmp1v1eA8SdSVu2PAeWNAUXFTAkgIbxRFUScsdbMyG2hdDiAie9t581PRdcRgcPWDPAoigj1xTgI9dbBTljlIJXQZ6+DuI3SpajfV8rksxRjqlgE5aec=
diff --git a/lib/requirement_checker.rb b/lib/requirement_checker.rb
--- a/lib/requirement_checker.rb
+++ b/lib/requirement_checker.rb
@@ -1,5 +1,10 @@
 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
diff --git a/test/test_requirement_checker.rb b/test/test_requirement_checker.rb
--- a/test/test_requirement_checker.rb
+++ b/test/test_requirement_checker.rb
@@ -38,14 +38,16 @@
       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