diff --git a/appium_lib.gemspec b/appium_lib.gemspec
index 8aa7f008..1c306d7e 100644
--- a/appium_lib.gemspec
+++ b/appium_lib.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'appium_lib_core', '>= 13.0.0', '< 14.0'
   s.add_dependency 'nokogiri', '~> 1.8', '>= 1.8.1'
-  s.add_dependency 'tomlrb', '>= 1.1', '< 3.0'
+  s.add_dependency 'tomlrb', '>= 1.1', '< 4.0'
 
   s.files = Dir.glob('lib/**/*.rb', base: __dir__) + %w[appium_lib.gemspec readme.md LICENSE-2.0.txt CHANGELOG.md]
   s.metadata['source_code_uri'] = s.homepage