diff --git a/mailgun-rails.gemspec b/mailgun-rails.gemspec
index 69bc2d6..01f36b3 100644
--- a/mailgun-rails.gemspec
+++ b/mailgun-rails.gemspec
@@ -17,11 +17,11 @@ Gem::Specification.new do |s|
 
   s.files = `git ls-files`.split("\n")
 
-  s.add_runtime_dependency 'activesupport', '>= 5.2'
+  s.add_runtime_dependency 'activesupport', '>= 6.0'
   s.add_runtime_dependency 'zeitwerk'
 
   s.add_development_dependency 'guard-rspec'
-  s.add_development_dependency 'rails', '>= 5.2'
+  s.add_development_dependency 'rails', '>= 6.0'
   s.add_development_dependency 'rake'
   s.add_development_dependency 'rspec'
   s.add_development_dependency 'rubocop'