diff --git a/Gemfile b/Gemfile
index 4214d92..1bed8aa 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,3 +2,8 @@ source 'https://rubygems.org'
 
 # Specify your gem's dependencies in readen.gemspec
 gemspec
+
+group :development, :test do
+  gem "pry"
+  gem "rake"
+end
diff --git a/lib/yomu.rb b/lib/yomu.rb
index e039861..16f52e5 100644
--- a/lib/yomu.rb
+++ b/lib/yomu.rb
@@ -3,6 +3,7 @@
 require 'net/http'
 require 'mime/types'
 require 'json'
+require 'time'
 
 require 'socket'
 require 'stringio'
diff --git a/lib/yomu/version.rb b/lib/yomu/version.rb
index 9c68582..0fac5ff 100644
--- a/lib/yomu/version.rb
+++ b/lib/yomu/version.rb
@@ -1,3 +1,3 @@
 class Yomu
-  VERSION = '0.2.4'
+  VERSION = '2.0.0'
 end
diff --git a/yomu.gemspec b/yomu.gemspec
index 43d75e2..2d2375c 100644
--- a/yomu.gemspec
+++ b/yomu.gemspec
@@ -18,10 +18,12 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_runtime_dependency 'mime-types', '~> 1.23'
-  spec.add_runtime_dependency 'json', '~> 1.8'
+  spec.add_runtime_dependency 'mime-types', '~> 3.4.1'
+  spec.add_runtime_dependency 'json', '~> 2.6'
 
-  spec.add_development_dependency 'bundler', '~> 1.3'
+  spec.add_development_dependency 'bundler', '~> 2.4.10'
   spec.add_development_dependency 'rake'
-  spec.add_development_dependency 'rspec', '~> 2.14'
+  spec.add_development_dependency 'rspec', '~> 3.12.0'
+
+  spec.required_ruby_version = '>= 2.7.3'
 end