diff --git a/default_value_for.gemspec b/default_value_for.gemspec
index 51d9a12..31ad91c 100644
--- a/default_value_for.gemspec
+++ b/default_value_for.gemspec
@@ -1,13 +1,13 @@
 Gem::Specification.new do |s|
   s.name                  = %q{default_value_for}
-  s.version               = "3.6.0"
+  s.version               = "4.0.0"
   s.summary               = %q{Provides a way to specify default values for ActiveRecord models}
   s.description           = %q{The default_value_for plugin allows one to define default values for ActiveRecord models in a declarative manner}
   s.email                 = %q{software-signing@phusion.nl}
   s.homepage              = %q{https://github.com/FooBarWidget/default_value_for}
   s.authors               = ["Hongli Lai"]
   s.license               = 'MIT'
-  s.required_ruby_version = '>= 1.9.3'
+  s.required_ruby_version = '>= 3.0.0'
   s.files                 = ['default_value_for.gemspec',
     'LICENSE.TXT', 'Rakefile', 'README.md', 'test.rb',
     'init.rb',