diff --git a/bittrex.gemspec b/bittrex.gemspec
index af81074..6cb8cc9 100644
--- a/bittrex.gemspec
+++ b/bittrex.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
-  spec.add_development_dependency "bundler", "~> 1.3"
+  spec.add_development_dependency "bundler", "~> 2.1"
   spec.add_development_dependency "rake"
   spec.add_development_dependency 'minitest'
   spec.add_development_dependency 'minitest-byebug'