diff --git a/gem/mulang.gemspec b/gem/mulang.gemspec
index efdae39d..36abe95e 100644
--- a/gem/mulang.gemspec
+++ b/gem/mulang.gemspec
@@ -17,13 +17,14 @@ Gem::Specification.new do |spec|
   spec.files         = Dir['lib/**/*', 'bin/**/*']
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib', 'bin']
-  spec.required_ruby_version = '>= 2.6', '< 3.2'
 
-  spec.add_dependency "mumukit-core", '> 1.0'
+  spec.add_dependency "mumukit-core", '~> 1.19'
 
   spec.add_development_dependency 'codeclimate-test-reporter'
   spec.add_development_dependency "activesupport", "~> 6.0"
   spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "pry", "~> 3.0"
+
+  spec.required_ruby_version = '>= 3.0'
 end