diff --git a/.travis.yml b/.travis.yml
index 63cb5f7..96f6e15 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,4 +8,3 @@ rvm:
   - 2.1
   - 2.0
   - 1.9
-  - rbx-2
diff --git a/Gemfile b/Gemfile
index 49b3c92..19aa13b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,4 +7,8 @@ group :development do
   gem 'test-unit', '~> 3.1'
 
   gem 'coveralls', :require => false
+
+  platform :ruby_18, :ruby_19 do
+    gem 'simplecov', '>= 0.10', '< 0.12'
+  end
 end