2 files changed, 20 insertions, 0 deletions
diff --git a/Library/Homebrew/requirements.rb b/Library/Homebrew/requirements.rb
index 3b6f0fe24..d0ebbe9cf 100644
--- a/Library/Homebrew/requirements.rb
+++ b/Library/Homebrew/requirements.rb
@@ -6,6 +6,7 @@ require 'requirements/mpi_dependency'
 require 'requirements/osxfuse_dependency'
 require 'requirements/python_dependency'
 require 'requirements/x11_dependency'
+require 'requirements/maximum_macos_requirement'
 
 class XcodeDependency < Requirement
   fatal true
diff --git a/Library/Homebrew/requirements/maximum_macos_requirement.rb b/Library/Homebrew/requirements/maximum_macos_requirement.rb
new file mode 100644
index 000000000..5efba641e
--- /dev/null
+++ b/Library/Homebrew/requirements/maximum_macos_requirement.rb
@@ -0,0 +1,19 @@
+require 'requirement'
+
+class MaximumMacOSRequirement < Requirement
+  fatal true
+
+  def initialize(tags)
+    @version = MacOS::Version.from_symbol(tags.first)
+    super
+  end
+
+  satisfy { MacOS.version <= @version }
+
+  def message
+    <<-EOS.undent
+      OS X #{@version.pretty_name} or older is required for stable.
+      Use `brew install devel or --HEAD` for newer.
+    EOS
+  end
+end