diff --git a/Gemfile b/Gemfile
index 6b97f98..e81e79b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,10 +4,10 @@ gem 'activesupport'
 gem 'therubyracer'
 # gem 'github-pages-health-check'
 gem 'html-proofer', group: :development
-gem 'jekyll'
+gem 'jekyll', '~> 3.8.4'
 group :jekyll_plugins do
   gem 'autoprefixer-rails'
-  gem 'bootstrap', '~> 4.1.1'
+  gem 'bootstrap', '~> 4.1.2'
   gem 'jekyll-assets', '~> 3.0.9'
   gem 'jekyll-avatar'
   gem 'jekyll-coffeescript'
@@ -52,8 +52,9 @@ gem 'kramdown'
 gem 'liquid'
 gem 'listen'
 gem 'mercenary'
-gem 'rack', '>= 2.0.6'
+gem 'rack', '~> 2.0.6'
 gem 'rouge'
 gem 'rubocop'
+gem 'rubyzip', '~> 1.2.2'
 # gem 'ruby-oembed'
 gem 'terminal-table'