diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e282e49..2a0a234 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -18,7 +18,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.1", "3.2", "3.3", "3.4", "jruby"]
+        ruby: ["3.0", "3.1", "3.2", "3.3", "3.4", "jruby"]
 
     steps:
       - name: Checkout code
diff --git a/.rubocop.yml b/.rubocop.yml
index b5d91fd..3dc06b7 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -4,7 +4,7 @@ plugins:
 
 AllCops:
   DisabledByDefault: false
-  TargetRubyVersion: 3.1
+  TargetRubyVersion: 3.0
   NewCops: enable
   SuggestExtensions: false
   Exclude:
diff --git a/Gemfile b/Gemfile
index 7f4f5e9..3829ec9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,4 +2,6 @@
 
 source 'https://rubygems.org'
 
+gem 'nokogiri', '~> 1.17.0'
+
 gemspec
diff --git a/Gemfile.lock b/Gemfile.lock
index c452002..385ea25 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -16,23 +16,9 @@ GEM
     language_server-protocol (3.17.0.4)
     lint_roller (1.1.0)
     method_source (1.1.0)
-    nokogiri (1.18.8-aarch64-linux-gnu)
-      racc (~> 1.4)
-    nokogiri (1.18.8-aarch64-linux-musl)
-      racc (~> 1.4)
-    nokogiri (1.18.8-arm-linux-gnu)
-      racc (~> 1.4)
-    nokogiri (1.18.8-arm-linux-musl)
-      racc (~> 1.4)
-    nokogiri (1.18.8-arm64-darwin)
-      racc (~> 1.4)
-    nokogiri (1.18.8-java)
-      racc (~> 1.4)
-    nokogiri (1.18.8-x86_64-darwin)
-      racc (~> 1.4)
-    nokogiri (1.18.8-x86_64-linux-gnu)
-      racc (~> 1.4)
-    nokogiri (1.18.8-x86_64-linux-musl)
+    mini_portile2 (2.8.9)
+    nokogiri (1.17.2)
+      mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     parallel (1.26.3)
     parser (3.3.7.4)
@@ -105,6 +91,7 @@ PLATFORMS
   x86_64-linux-musl
 
 DEPENDENCIES
+  nokogiri (~> 1.17.0)
   pry
   rake
   rspec (~> 3.0)
@@ -115,4 +102,4 @@ DEPENDENCIES
   yard (>= 0.5.8)
 
 BUNDLED WITH
-   2.6.8
+   2.5.23
diff --git a/lib/xpath/union.rb b/lib/xpath/union.rb
index 8fb169c..59b9796 100644
--- a/lib/xpath/union.rb
+++ b/lib/xpath/union.rb
@@ -15,8 +15,8 @@ def expression
       :union
     end
 
-    def each(&)
-      arguments.each(&)
+    def each(&block)
+      arguments.each(&block)
     end
 
     def method_missing(*args) # rubocop:disable Style/MissingRespondToMissing