diff --git a/Gemfile.development_dependencies b/Gemfile.development_dependencies
index 38e9281ccd..c9f69a0547 100644
--- a/Gemfile.development_dependencies
+++ b/Gemfile.development_dependencies
@@ -20,7 +20,7 @@ gem "sdoc", group: :doc
 gem "sprockets"
 
 gem "amazing_print"
-gem "mini_racer"
+gem "mini_racer", "0.4.0"
 
 group :development, :test do
   gem "listen"
diff --git a/lib/generators/react_on_rails/base_generator.rb b/lib/generators/react_on_rails/base_generator.rb
index 9ea2fbe864..988785c341 100644
--- a/lib/generators/react_on_rails/base_generator.rb
+++ b/lib/generators/react_on_rails/base_generator.rb
@@ -71,7 +71,7 @@ def copy_webpacker_config
       end
 
       def add_base_gems_to_gemfile
-        gem "mini_racer", platforms: :ruby
+        gem "mini_racer", "0.4.0", platforms: :ruby
         run "bundle"
       end
 
diff --git a/rakelib/examples.rake b/rakelib/examples.rake
index 0ad09064d5..ce23f67ed3 100644
--- a/rakelib/examples.rake
+++ b/rakelib/examples.rake
@@ -34,6 +34,7 @@ namespace :examples do # rubocop:disable Metrics/BlockLength
       sh_in_dir(examples_dir, "rails new #{example_type.name} #{example_type.rails_options}")
       sh_in_dir(example_type.dir, "touch .gitignore")
       copy_generator_webpacker_yml_to(example_type.dir)
+      sh_in_dir(example_type.dir, "bundle add webpacker --version 6.0.0.rc.6")
       sh_in_dir(example_type.dir, "rake webpacker:install")
       sh_in_dir(example_type.dir, "bundle binstubs --path=#{example_type.dir}/bin webpacker")
       append_to_gemfile(example_type.gemfile, example_type.required_gems)
diff --git a/react_on_rails.gemspec b/react_on_rails.gemspec
index fcd76deb2b..fb281e9af2 100644
--- a/react_on_rails.gemspec
+++ b/react_on_rails.gemspec
@@ -30,7 +30,7 @@ Gem::Specification.new do |s|
   s.add_dependency "execjs", "~> 2.5"
   s.add_dependency "rails", ">= 3.2"
   s.add_dependency "rainbow", "~> 3.0"
-  s.add_dependency "webpacker", ">= 4.0"
+  s.add_dependency "webpacker", "6.0.0.rc.6"
 
   s.add_development_dependency "bundler", "~> 2"
   s.add_development_dependency "gem-release"