diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c195d5cb..5ea1f463 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -21,6 +21,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
+          - '4.0'
           - '3.4'
           - '3.3'
           - '3.2'
diff --git a/webauthn.gemspec b/webauthn.gemspec
index a7bdabe2..7d7bc8a1 100644
--- a/webauthn.gemspec
+++ b/webauthn.gemspec
@@ -41,7 +41,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency "safety_net_attestation", "~> 0.5.0"
   spec.add_dependency "tpm-key_attestation", "~> 0.14.0"
 
-  spec.add_development_dependency "bundler", ">= 1.17", "< 3.0"
+  spec.add_development_dependency "bundler", ">= 1.17", "< 5.0"
   spec.add_development_dependency "byebug", "~> 11.0"
   spec.add_development_dependency "rake", "~> 13.0"
   spec.add_development_dependency "rspec", "~> 3.8"