diff --git a/Gemfile b/Gemfile
index 8cc610a8..e04240a4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,10 +1,5 @@
 source 'https://rubygems.org'
 
-platforms :ruby_19 do
-  gem 'mime-types', '~> 2.6'
-  gem 'rest-client', '~> 1.8'
-end
-
 group :test do
   gem 'rake'
   gem 'dotenv'
diff --git a/README.md b/README.md
index ac05f79b..c7b122ad 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ version `3.0.0` has [breaking changes](https://github.com/stripe-ruby-mock/strip
 
 ### Requirements
 
-* ruby >= 2.6.0
+* ruby >= 2.7.0
 * stripe >= 5.0.0
 
 ### Specifications
diff --git a/stripe-ruby-mock.gemspec b/stripe-ruby-mock.gemspec
index e53963d8..f8a28d6c 100644
--- a/stripe-ruby-mock.gemspec
+++ b/stripe-ruby-mock.gemspec
@@ -26,7 +26,6 @@ Gem::Specification.new do |gem|
   gem.add_dependency 'multi_json', '~> 1.0'
   gem.add_dependency 'dante', '>= 0.2.0'
 
-  gem.add_development_dependency 'rspec', '~> 3.7.0'
-  gem.add_development_dependency 'rubygems-tasks', '~> 0.2'
+  gem.add_development_dependency 'rspec', '~> 3.13.0'
   gem.add_development_dependency 'thin', '~> 1.8.1'
 end