diff --git a/.rubocop.yml b/.rubocop.yml
index c89cb3b5..d394832d 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -3,7 +3,7 @@ require:
 
 AllCops:
   DisabledByDefault: false
-  TargetRubyVersion: 2.2.2
+  TargetRubyVersion: 2.3.0
   Exclude:
       - 'capybara.gemspec'
 
diff --git a/.travis.yml b/.travis.yml
index 4b86878b..9daaa76a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ dist: trusty
 services:
   - docker
 rvm:
-  - 2.5.0
+  - 2.5.1
   - 2.3.6
   - jruby-9.1.16.0
 gemfile:
@@ -33,7 +33,7 @@ cache:
 matrix:
   include:
     - gemfile: Gemfile
-      rvm: 2.5.0
+      rvm: 2.5.1
       env: CAPYBARA_CHROME_REMOTE=true
     - gemfile: gemfiles/Gemfile.rspec-34
       rvm: 2.3.6
@@ -44,10 +44,10 @@ matrix:
           packages:
             - awesome
     - gemfile: Gemfile
-      rvm: 2.2.2
+      rvm: 2.5.1
       env: HEADLESS=true
     - gemfile: gemfiles/Gemfile.beta-versions
-      rvm: 2.5.0
+      rvm: 2.5.1
       env: CAPYBARA_FF=true
       addons:
         firefox: latest-beta
@@ -70,11 +70,10 @@ matrix:
   allow_failures:
     - gemfile: gemfiles/Gemfile.beta-versions
     - gemfile: gemfiles/Gemfile.edge-marionette
-    - rvm: rbx-3
     - env: CAPYBARA_CHROME_REMOTE=true
 before_install:
   - gem update --system
-  # - gem update bundler
+  - gem install bundler
   - if [[ $BUNDLE_GEMFILE =~ Gemfile.edge-marionette$ ]]; then
       pushd ..;
       git clone --depth 1 https://github.com/SeleniumHQ/selenium.git;
diff --git a/appveyor.yml b/appveyor.yml
index b9c2a4cf..d683ec0a 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -10,7 +10,7 @@ environment:
     - RUBY_VERSION: 25
       CAPYBARA_IE: true
       BUNDLE_GEMFILE: gemfiles/Gemfile.ie
-    - RUBY_VERSION: 22
+    - RUBY_VERSION: 23
 
 matrix:
   allow_failures:
diff --git a/capybara.gemspec b/capybara.gemspec
index 70008701..8164af30 100644
--- a/capybara.gemspec
+++ b/capybara.gemspec
@@ -6,7 +6,7 @@ require 'capybara/version'
 Gem::Specification.new do |s|
   s.name = "capybara"
   s.version = Capybara::VERSION
-  s.required_ruby_version = ">= 2.2.2"
+  s.required_ruby_version = ">= 2.3.0"
   s.license = "MIT"
 
   s.authors = ["Thomas Walpole", "Jonas Nicklas"]
diff --git a/lib/capybara/driver/base.rb b/lib/capybara/driver/base.rb
index 6f104014..b89ba425 100644
--- a/lib/capybara/driver/base.rb
+++ b/lib/capybara/driver/base.rb
@@ -155,6 +155,6 @@ class Capybara::Driver::Base
   end
 
   def session_options
-    (@session && @session.config) || Capybara.session_options
+    @session&.config || Capybara.session_options
   end
 end
diff --git a/lib/capybara/node/actions.rb b/lib/capybara/node/actions.rb
index 8fe3647d..e108327e 100644
--- a/lib/capybara/node/actions.rb
+++ b/lib/capybara/node/actions.rb
@@ -307,7 +307,7 @@ module Capybara
         end
       end
 
-      UPDATE_STYLE_SCRIPT = <<-'JS'.freeze
+      UPDATE_STYLE_SCRIPT = <<-'JS'
         var el = arguments[0];
         el.capybara_style_cache = el.style.cssText;
         var css = arguments[1];
@@ -318,7 +318,7 @@ module Capybara
         }
       JS
 
-      RESET_STYLE_SCRIPT = <<-'JS'.freeze
+      RESET_STYLE_SCRIPT = <<-'JS'
         var el = arguments[0];
         if (el.hasOwnProperty('capybara_style_cache')) {
           el.style.cssText = el.capybara_style_cache;
@@ -326,7 +326,7 @@ module Capybara
         }
       JS
 
-      DATALIST_OPTIONS_SCRIPT = <<-'JS'.freeze
+      DATALIST_OPTIONS_SCRIPT = <<-'JS'
         Array.prototype.slice.call((arguments[0].list||{}).options || []).
           filter(function(el){ return !el.disabled }).
           map(function(el){ return { "value": el.value, "label": el.label} })
diff --git a/lib/capybara/node/matchers.rb b/lib/capybara/node/matchers.rb
index 3a819342..4316eb8a 100644
--- a/lib/capybara/node/matchers.rb
+++ b/lib/capybara/node/matchers.rb
@@ -596,7 +596,7 @@ module Capybara
       #
       def assert_text(*args)
         _verify_text(args) do |count, query|
-          unless query.matches_count?(count) && ((count > 0) || query.expects_none?)
+          unless query.matches_count?(count) && (count.positive? || query.expects_none?)
             raise Capybara::ExpectationNotMet, query.failure_message
           end
         end
@@ -612,7 +612,7 @@ module Capybara
       #
       def assert_no_text(*args)
         _verify_text(args) do |count, query|
-          if query.matches_count?(count) && ((count > 0) || query.expects_none?)
+          if query.matches_count?(count) && (count.positive? || query.expects_none?)
             raise Capybara::ExpectationNotMet, query.negative_failure_message
           end
         end
diff --git a/lib/capybara/queries/ancestor_query.rb b/lib/capybara/queries/ancestor_query.rb
index 94f92cd2..824b9aaa 100644
--- a/lib/capybara/queries/ancestor_query.rb
+++ b/lib/capybara/queries/ancestor_query.rb
@@ -13,7 +13,7 @@ module Capybara
       end
 
       def description
-        child_query = @child_node && @child_node.instance_variable_get(:@query)
+        child_query = @child_node&.instance_variable_get(:@query)
         desc = super
         desc += " that is an ancestor of #{child_query.description}" if child_query
         desc
diff --git a/lib/capybara/queries/base_query.rb b/lib/capybara/queries/base_query.rb
index 3757c32f..b9ab4dec 100644
--- a/lib/capybara/queries/base_query.rb
+++ b/lib/capybara/queries/base_query.rb
@@ -59,11 +59,11 @@ module Capybara
       # Generates a failure message from the query description and count options.
       #
       def failure_message
-        String.new("expected to find #{description}") << count_message
+        +"expected to find #{description}" << count_message
       end
 
       def negative_failure_message
-        String.new("expected not to find #{description}") << count_message
+        +"expected not to find #{description}" << count_message
       end
 
     private
@@ -73,7 +73,7 @@ module Capybara
       end
 
       def count_message
-        message = "".dup
+        message = +""
         if options[:count]
           message << " #{options[:count]} #{Capybara::Helpers.declension('time', 'times', options[:count])}"
         elsif options[:between]
diff --git a/lib/capybara/queries/current_path_query.rb b/lib/capybara/queries/current_path_query.rb
index 8d2cf3a2..255237c3 100644
--- a/lib/capybara/queries/current_path_query.rb
+++ b/lib/capybara/queries/current_path_query.rb
@@ -19,7 +19,7 @@ module Capybara
       def resolves_for?(session)
         uri = ::Addressable::URI.parse(session.current_url)
         uri.query = nil if uri && options[:ignore_query]
-        @actual_path = options[:url] ? uri.to_s : uri && uri.request_uri
+        @actual_path = options[:url] ? uri.to_s : uri&.request_uri
 
         if @expected_path.is_a? Regexp
           @actual_path.to_s.match(@expected_path)
diff --git a/lib/capybara/queries/selector_query.rb b/lib/capybara/queries/selector_query.rb
index ce9b4aae..057205bd 100644
--- a/lib/capybara/queries/selector_query.rb
+++ b/lib/capybara/queries/selector_query.rb
@@ -31,7 +31,7 @@ module Capybara
       def label; selector.label || selector.name; end
 
       def description
-        @description = "".dup
+        @description = +""
         @description << "visible " if visible == :visible
         @description << "non-visible " if visible == :hidden
         @description << "#{label} #{locator.inspect}"
diff --git a/lib/capybara/queries/sibling_query.rb b/lib/capybara/queries/sibling_query.rb
index e2066131..2eb45c90 100644
--- a/lib/capybara/queries/sibling_query.rb
+++ b/lib/capybara/queries/sibling_query.rb
@@ -16,7 +16,7 @@ module Capybara
 
       def description
         desc = super
-        sibling_query = @sibling_node && @sibling_node.instance_variable_get(:@query)
+        sibling_query = @sibling_node&.instance_variable_get(:@query)
         desc += " that is a sibling of #{sibling_query.description}" if sibling_query
         desc
       end
diff --git a/lib/capybara/queries/text_query.rb b/lib/capybara/queries/text_query.rb
index 32c62859..aec03b59 100644
--- a/lib/capybara/queries/text_query.rb
+++ b/lib/capybara/queries/text_query.rb
@@ -50,7 +50,7 @@ module Capybara
       end
 
       def build_message(report_on_invisible)
-        message = "".dup
+        message = +""
         unless (COUNT_KEYS & @options.keys).empty?
           message << " but found #{@count} #{Capybara::Helpers.declension('time', 'times', @count)}"
         end
diff --git a/lib/capybara/result.rb b/lib/capybara/result.rb
index 93b20b56..acae5ea1 100644
--- a/lib/capybara/result.rb
+++ b/lib/capybara/result.rb
@@ -50,7 +50,7 @@ module Capybara
       idx, length = args
       max_idx = case idx
       when Integer
-        if idx >= 0
+        if !idx.negative?
           length.nil? ? idx : idx + length - 1
         else
           nil
diff --git a/lib/capybara/selector.rb b/lib/capybara/selector.rb
index 1bbd9ad3..6f9b97df 100644
--- a/lib/capybara/selector.rb
+++ b/lib/capybara/selector.rb
@@ -11,7 +11,7 @@ Capybara::Selector::FilterSet.add(:_field) do
   expression_filter(:placeholder) { |xpath, val| xpath[XPath.attr(:placeholder) == val] }
 
   describe do |checked: nil, unchecked: nil, disabled: nil, multiple: nil, **_options|
-    desc, states = "".dup, []
+    desc, states = +"", []
     states << 'checked' if checked || (unchecked == false)
     states << 'not checked' if unchecked || (checked == false)
     states << 'disabled' if disabled == true
@@ -94,7 +94,7 @@ Capybara.add_selector(:field) do
     with.is_a?(Regexp) ? node.value =~ with : node.value == with.to_s
   end
   describe do |type: nil, **options|
-    desc = "".dup
+    desc = +""
     (expression_filters.keys - [:type]).each { |ef| desc << " with #{ef} #{options[ef]}" if options.key?(ef) }
     desc << " of type #{type.inspect}" if type
     desc << " with value #{options[:with].to_s.inspect}" if options.key?(:with)
@@ -170,7 +170,7 @@ Capybara.add_selector(:link) do
   end
 
   describe do |**options|
-    desc = "".dup
+    desc = +""
     desc << " with href #{options[:href].inspect}" if options[:href]
     desc << " with no href attribute" if options.fetch(:href, true).nil?
   end
@@ -217,7 +217,7 @@ Capybara.add_selector(:button) do
   filter(:disabled, :boolean, default: false, skip_if: :all) { |node, value| !(value ^ node.disabled?) }
 
   describe do |disabled: nil, **options|
-    desc = "".dup
+    desc = +""
     desc << " that is disabled" if disabled == true
     desc << describe_all_expression_filters(options)
     desc
@@ -277,7 +277,7 @@ Capybara.add_selector(:fillable_field) do
   end
 
   describe do |options|
-    desc = "".dup
+    desc = +""
     desc << describe_all_expression_filters(options)
     desc << " with value #{options[:with].to_s.inspect}" if options.key?(:with)
     desc
@@ -310,7 +310,7 @@ Capybara.add_selector(:radio_button) do
   filter(:option) { |node, value| node.value == value.to_s }
 
   describe do |option: nil, **options|
-    desc = "".dup
+    desc = +""
     desc << " with value #{option.inspect}" if option
     desc << describe_all_expression_filters(options)
     desc
@@ -341,7 +341,7 @@ Capybara.add_selector(:checkbox) do
   filter(:option) { |node, value| node.value == value.to_s }
 
   describe do |option: nil, **options|
-    desc = "".dup
+    desc = +""
     desc << " with value #{option.inspect}" if option
     desc << describe_all_expression_filters(options)
     desc
@@ -401,7 +401,7 @@ Capybara.add_selector(:select) do
   end
 
   describe do |options: nil, with_options: nil, selected: nil, with_selected: nil, **opts|
-    desc = "".dup
+    desc = +""
     desc << " with options #{options.inspect}" if options
     desc << " with at least options #{with_options.inspect}" if with_options
     desc << " with #{selected.inspect} selected" if selected
@@ -434,7 +434,7 @@ Capybara.add_selector(:datalist_input) do
   end
 
   describe do |options: nil, with_options: nil, **opts|
-    desc = "".dup
+    desc = +""
     desc << " with options #{options.inspect}" if options
     desc << " with at least options #{with_options.inspect}" if with_options
     desc << describe_all_expression_filters(opts)
@@ -461,7 +461,7 @@ Capybara.add_selector(:option) do
   filter(:selected, :boolean) { |node, value| !(value ^ node.selected?) }
 
   describe do |**options|
-    desc = "".dup
+    desc = +""
     desc << " that is#{' not' unless options[:disabled]} disabled" if options.key?(:disabled)
     desc << " that is#{' not' unless options[:selected]} selected" if options.key?(:selected)
     desc
@@ -481,7 +481,7 @@ Capybara.add_selector(:datalist_option) do
   filter(:disabled, :boolean) { |node, value| !(value ^ node.disabled?) }
 
   describe do |**options|
-    desc = "".dup
+    desc = +""
     desc << " that is#{' not' unless options[:disabled]} disabled" if options.key?(:disabled)
     desc
   end
@@ -508,7 +508,7 @@ Capybara.add_selector(:file_field) do
   filter_set(:_field, %i[disabled multiple name])
 
   describe do |**options|
-    desc = "".dup
+    desc = +""
     desc << describe_all_expression_filters(options)
     desc
   end
@@ -550,7 +550,7 @@ Capybara.add_selector(:label) do
   end
 
   describe do |**options|
-    desc = "".dup
+    desc = +""
     desc << " for #{options[:for]}" if options[:for]
     desc
   end
@@ -574,7 +574,7 @@ Capybara.add_selector(:table) do
   end
 
   describe do |caption: nil, **_options|
-    desc = "".dup
+    desc = +""
     desc << " with caption #{caption}" if caption
     desc
   end
@@ -598,7 +598,7 @@ Capybara.add_selector(:frame) do
   end
 
   describe do |name: nil, **_options|
-    desc = "".dup
+    desc = +""
     desc << " with name #{name}" if name
     desc
   end
diff --git a/lib/capybara/selector/css.rb b/lib/capybara/selector/css.rb
index 22437c6c..11a75a66 100644
--- a/lib/capybara/selector/css.rb
+++ b/lib/capybara/selector/css.rb
@@ -5,7 +5,7 @@ module Capybara
     class CSS
       def self.escape(str)
         value = str.dup
-        out = "".dup
+        out = +""
         out << value.slice!(0...1) if value =~ /^[-_]/
         out << (value[0] =~ NMSTART ? value.slice!(0...1) : escape_char(value.slice!(0...1)))
         out << value.gsub(/[^a-zA-Z0-9_-]/) { |c| escape_char c }
@@ -16,7 +16,7 @@ module Capybara
         c =~ %r{[ -/:-~]} ? "\\#{c}" : format("\\%06x", c.ord)
       end
 
-      S = '\u{80}-\u{D7FF}\u{E000}-\u{FFFD}\u{10000}-\u{10FFFF}'.freeze
+      S = '\u{80}-\u{D7FF}\u{E000}-\u{FFFD}\u{10000}-\u{10FFFF}'
       H = /[0-9a-fA-F]/
       UNICODE  = /\\#{H}{1,6}[ \t\r\n\f]?/
       NONASCII = /[#{S}]/
diff --git a/lib/capybara/selector/selector.rb b/lib/capybara/selector/selector.rb
index 48453c90..cd7239ed 100644
--- a/lib/capybara/selector/selector.rb
+++ b/lib/capybara/selector/selector.rb
@@ -168,7 +168,7 @@ module Capybara
     # @return [Boolean]           Whether or not to use this selector
     #
     def match?(locator)
-      @match and @match.call(locator)
+      @match&.call(locator)
     end
 
     ##
diff --git a/lib/capybara/selenium/driver.rb b/lib/capybara/selenium/driver.rb
index d7836434..1e05021b 100644
--- a/lib/capybara/selenium/driver.rb
+++ b/lib/capybara/selenium/driver.rb
@@ -263,7 +263,7 @@ class Capybara::Selenium::Driver < Capybara::Driver::Base
   end
 
   def quit
-    @browser.quit if @browser
+    @browser&.quit
   rescue Selenium::WebDriver::Error::SessionNotCreatedError, Errno::ECONNREFUSED
     # Browser must have already gone
   rescue Selenium::WebDriver::Error::UnknownError => e
diff --git a/lib/capybara/server.rb b/lib/capybara/server.rb
index 9e3c2452..77a12742 100644
--- a/lib/capybara/server.rb
+++ b/lib/capybara/server.rb
@@ -33,7 +33,7 @@ module Capybara
       end
 
       def pending_requests?
-        @counter.value > 0
+        @counter.value.positive?
       end
 
       def call(env)
@@ -86,7 +86,7 @@ module Capybara
     end
 
     def responsive?
-      return false if @server_thread && @server_thread.join(0)
+      return false if @server_thread&.join(0)
 
       begin
         res = if !@using_ssl
@@ -162,7 +162,7 @@ module Capybara
       server = TCPServer.new(host, 0)
       server.addr[1]
     ensure
-      server.close if server
+      server&.close
     end
   end
 end
diff --git a/lib/capybara/session.rb b/lib/capybara/session.rb
index 8e228353..cd86adf3 100644
--- a/lib/capybara/session.rb
+++ b/lib/capybara/session.rb
@@ -126,7 +126,7 @@ module Capybara
         driver.reset!
         @touched = false
       end
-      @server.wait_for_pending_requests if @server
+      @server&.wait_for_pending_requests
       raise_server_error!
     end
     alias_method :cleanup!, :reset!
diff --git a/lib/capybara/spec/spec_helper.rb b/lib/capybara/spec/spec_helper.rb
index 76be66ae..80c6fd2c 100644
--- a/lib/capybara/spec/spec_helper.rb
+++ b/lib/capybara/spec/spec_helper.rb
@@ -86,7 +86,7 @@ module Capybara
         Capybara::Session.class_variable_set(:@@instance_created, false) # Work around limit on when threadsafe can be changed
         Capybara.threadsafe = bool
         session = session.current_session if session.respond_to?(:current_session)
-        session.instance_variable_set(:@config, nil) if session
+        session&.instance_variable_set(:@config, nil)
       end
     end
 
diff --git a/lib/capybara/version.rb b/lib/capybara/version.rb
index 1af19ccb..a06289fc 100644
--- a/lib/capybara/version.rb
+++ b/lib/capybara/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Capybara
-  VERSION = '3.1.0'.freeze
+  VERSION = '3.1.0'
 end