diff --git a/.gitignore b/.gitignore
index c8fbad2..4403e7a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@
 .sass-cache
 _site
 Gemfile.lock
+.jekyll-cache
 /public
diff --git a/html5up-readonly.gemspec b/html5up-readonly.gemspec
index a88d5ef..38870ec 100644
--- a/html5up-readonly.gemspec
+++ b/html5up-readonly.gemspec
@@ -12,9 +12,9 @@ Gem::Specification.new do |spec|
 
   spec.files         = `git ls-files -z`.split("\x0").select { |f| f.match(%r!^(assets|_layouts|_includes|_sass|LICENSE|README)!i) }
 
-  spec.add_runtime_dependency "jekyll", "~> 3.8"
-  spec.add_runtime_dependency "jekyll-feed", "~> 0.9"
-  spec.add_runtime_dependency "jekyll-seo-tag", "~> 2.1"
+  spec.add_runtime_dependency "jekyll", "~> 4.0"
+  spec.add_runtime_dependency "jekyll-feed", "~> 0.13"
+  spec.add_runtime_dependency "jekyll-seo-tag", "~> 2.6"
 
   spec.add_development_dependency "bundler", "~> 2.0"
   spec.add_development_dependency "rake", "~> 12.0"