diff --git a/html-pipeline.gemspec b/html-pipeline.gemspec
index 8b170499..154d209c 100644
--- a/html-pipeline.gemspec
+++ b/html-pipeline.gemspec
@@ -16,12 +16,12 @@ Gem::Specification.new do |gem|
gem.require_paths = ["lib"]
gem.add_dependency "gemoji", "~> 1.0"
- gem.add_dependency "nokogiri", "~> 1.4"
+ gem.add_dependency "nokogiri", RUBY_VERSION < "1.9.2" ? [">= 1.4", "< 1.6"] : "~> 1.4"
gem.add_dependency "github-markdown", "~> 0.5"
- gem.add_dependency "sanitize", "~> 2.0"
+ gem.add_dependency "sanitize", RUBY_VERSION < "1.9.2" ? [">= 2", "< 2.0.4"] : "~> 2.0"
gem.add_dependency "rinku", "~> 1.7"
gem.add_dependency "escape_utils", "~> 0.3"
- gem.add_dependency "activesupport", ">= 2"
+ gem.add_dependency "activesupport", RUBY_VERSION < "1.9.3" ? [">= 2", "< 4"] : ">= 2"
gem.add_development_dependency "github-linguist", "~> 2.6.2"
end