diff --git a/.rubocop.yml b/.rubocop.yml
index 847f297..acdcaa7 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -14,7 +14,7 @@ plugins:
   - rubocop-rake
 
 AllCops:
-  TargetRubyVersion: 3.3 # 4.0 not yet afailable Tue Dec 30 15:07:23 PST 2025
+  TargetRubyVersion: 4.0
   NewCops: enable
   Exclude:
     - 'spec/fixture_files/**/*'
diff --git a/Dockerfile b/Dockerfile
index d43a45c..cd8ccb9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,10 +2,10 @@
 #
 # For development:
 # docker run -it -v $PWD:/project -v $PWD:/tmp/src -w /tmp/src ruby_language_server sh -c 'bundle && guard'
-FROM ruby:3.3-alpine
+FROM ruby:4.0-alpine
 LABEL maintainer="kurt@CircleW.org"
 
-RUN gem update bundler
+# RUN gem update bundler - Skipping as Ruby 4.0 comes with compatible bundler
 
 # Needed for byebug and some other gems
 RUN apk update
@@ -19,7 +19,7 @@ RUN curl -O -L https://github.com/mateusza/SQLite-Levenshtein/archive/master.zip
 RUN unzip master.zip
 WORKDIR /usr/local/src/SQLite-Levenshtein-master
 RUN ./configure
-RUN make -j 8 install
+RUN make install
 
 WORKDIR /app
 RUN rm -rf /usr/local/src
diff --git a/ruby_language_server.gemspec b/ruby_language_server.gemspec
index 677c420..7f18410 100644
--- a/ruby_language_server.gemspec
+++ b/ruby_language_server.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
   spec.description   = 'Provide a language server implementation for ruby in ruby.  See https://microsoft.github.io/language-server-protocol/ "A Language Server is meant to provide the language-specific smarts and communicate with development tools over a protocol that enables inter-process communication."'
   spec.homepage      = 'https://github.com/kwerle/ruby_language_server'
   spec.license       = 'MIT'
-  spec.required_ruby_version = '>=3.3.0'
+  spec.required_ruby_version = '>=4.0.0'
 
   # Prevent pushing this gem to RubyGems.org. To allow pushes either set the 'allowed_push_host'
   # to allow pushing to a single host or delete this section to allow pushing to any host.
diff --git a/spec/lib/ruby_language_server/completion_spec.rb b/spec/lib/ruby_language_server/completion_spec.rb
index 43e3b0b..8b01541 100644
--- a/spec/lib/ruby_language_server/completion_spec.rb
+++ b/spec/lib/ruby_language_server/completion_spec.rb
@@ -42,12 +42,12 @@ def baz; end
   let(:all_scopes) { @scope_parser.root_scope.self_and_descendants }
   let(:nar_naz_scope) { all_scopes.find_by_path('Foo::Nar#naz') }
 
-  def scope_completions(*args)
-    RubyLanguageServer::Completion.send(:scope_completions, *args)
+  def scope_completions(*)
+    RubyLanguageServer::Completion.send(:scope_completions, *)
   end
 
-  def scope_completions_in_target_context(*args)
-    RubyLanguageServer::Completion.send(:scope_completions_in_target_context, *args)
+  def scope_completions_in_target_context(*)
+    RubyLanguageServer::Completion.send(:scope_completions_in_target_context, *)
   end
 
   describe '.completion' do