diff --git a/.travis.yml b/.travis.yml
index 9bb47e9..f10c60c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,14 +4,14 @@ cache: bundler
 
 rvm:
   - ruby-head
-  - 2.6.0
-  - 2.5.1
-  - 2.4.4
-  - 2.3.7
+  - 2.6.1
+  - 2.5.3
+  - 2.4.5
+  - 2.3.8
 
 before_install:
   - gem update --system
-  - gem install bundler
+  - gem install bundler -v "~> 2.0"
 
 gemfile:
   - gemfiles/rack_2_0.gemfile
diff --git a/rack-attack.gemspec b/rack-attack.gemspec
index 3722081..bbee3e0 100644
--- a/rack-attack.gemspec
+++ b/rack-attack.gemspec
@@ -33,7 +33,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'rack', ">= 1.0", "< 3"
 
   s.add_development_dependency 'appraisal', '~> 2.2'
-  s.add_development_dependency "bundler", "~> 1.16"
+  s.add_development_dependency "bundler", ">= 1.17", "< 3.0"
   s.add_development_dependency 'minitest', "~> 5.11"
   s.add_development_dependency "minitest-stub-const", "~> 0.6"
   s.add_development_dependency 'rack-test', "~> 1.0"