diff --git a/rackstash.gemspec b/rackstash.gemspec
index 0cb888f..51e2423 100644
--- a/rackstash.gemspec
+++ b/rackstash.gemspec
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 #
-# Copyright 2017 Holger Just
+# Copyright 2017 - 2019 Holger Just
 #
 # This software may be modified and distributed under the terms
 # of the MIT license. See the LICENSE.txt file for details.
@@ -39,8 +39,8 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'concurrent-ruby', '~> 1.0', '>= 1.0.2'
 
-  spec.add_development_dependency 'bundler', '~> 1.12'
-  spec.add_development_dependency 'rake', '~> 10.0'
+  spec.add_development_dependency 'bundler', '>= 1.12'
+  spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rspec', '~> 3.0'
 
   spec.add_development_dependency 'coveralls', '~> 0.8.20'