diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f6dac23..80cfb87 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        RUBY_VERSION: [2.2, 2.3, 2.5, 2.6]
+        RUBY_VERSION: [2.6, 2.7]
     steps:
       - name: Check out code
         uses: actions/checkout@v4
diff --git a/aptible-auth.gemspec b/aptible-auth.gemspec
index 62dca05..4f4f7a3 100644
--- a/aptible-auth.gemspec
+++ b/aptible-auth.gemspec
@@ -21,9 +21,10 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
 
   spec.add_dependency 'aptible-resource', '~> 1.0'
+  spec.add_dependency 'concurrent-ruby', '1.3.4'
   spec.add_dependency 'gem_config'
   spec.add_dependency 'multipart-post', '2.1.1'
-  spec.add_dependency 'oauth2', '1.4.7'
+  spec.add_dependency 'oauth2', '2.0.9'
 
   spec.add_development_dependency 'aptible-tasks', '>= 0.6.0'
   spec.add_development_dependency 'pry'
diff --git a/spec/oauth2/lib/token_exchange_spec.rb b/spec/oauth2/lib/token_exchange_spec.rb
index 4692a44..c4432ee 100644
--- a/spec/oauth2/lib/token_exchange_spec.rb
+++ b/spec/oauth2/lib/token_exchange_spec.rb
@@ -4,14 +4,14 @@
 RSpec.describe OAuth2::Strategy::TokenExchange do
   let(:client) do
     cli = OAuth2::Client.new('abc', 'def', :site => 'http://api.example.com')
-    cli.connection.build do |b|
+    cli.connection.builder.build do |b|
       b.adapter :test do |stub|
         stub.post('/oauth/token') do |env|
           case @mode
           when 'formencoded'
             [200, {'Content-Type' => 'application/x-www-form-urlencoded'}, 'expires_in=600&access_token=salmon&refresh_token=trout']
           when 'json'
-            [200, {'Content-Type' => 'application/json'}, '{"expires_in":600,"access_token":"salmon","refresh_token":"trout"}']
+            [200, {'Content-Type' => 'application/json'}, {"expires_in" => 600, "access_token" => "salmon", "refresh_token" => "trout"}]
           end
         end
       end