diff --git a/Gemfile b/Gemfile
index 5f7d872..a843d5c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,7 @@ if Gem::Version.new(Bundler::VERSION) < Gem::Version.new('1.5.0')
 end
 
 gem "rails", "4.2.7.1"
+gem "addressable", "2.4.0" if RUBY_VERSION < "2.0"
 gem "jquery-rails", "~> 3.1.4"
 gem "coderay", "~> 1.1.0"
 gem "builder", ">= 3.0.4"
@@ -93,7 +94,7 @@ else
 end
 
 group :development do
-  gem "rdoc", ">= 2.4.2"
+  gem "rdoc", "~> 4.3"
   gem "yard"
 end
 
@@ -104,7 +105,7 @@ group :test do
   gem "simplecov", "~> 0.9.1", :require => false
   # For running UI tests
   gem "capybara"
-  gem "selenium-webdriver"
+  gem "selenium-webdriver", "~> 2.53.4"
 end
 
 local_gemfile = File.join(File.dirname(__FILE__), "Gemfile.local")