diff --git a/.rubocop.yml b/.rubocop.yml
index 6cd11eb..01f9380 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,3 +1,6 @@
+AllCops:
+  DisplayCopNames: true
+
 ## Styles ######################################################################
 
 Style/AlignParameters:
@@ -31,18 +34,12 @@ Style/Lambda:
 Style/MultilineOperationIndentation:
   EnforcedStyle: indented
 
-# A bit useless restriction, that makes impossible aligning code like this:
-#
-#   redis do |conn|
-#     conn.hset    :k1, now
-#     conn.hincrby :k2, 123
-#   end
-SingleSpaceBeforeFirstArg:
-  Enabled: false
-
 Style/StringLiterals:
   EnforcedStyle: double_quotes
 
+Style/EmptyCaseCondition:
+  Enabled: false
+
 # Not all trivial readers/writers can be defined with attr_* methods
 #
 #   class Example < SimpleDelegator
diff --git a/.travis.yml b/.travis.yml
index beca66c..a6d8d16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,17 +4,12 @@ env:
     - JRUBY_OPTS="$JRUBY_OPTS --debug"
 language: ruby
 rvm:
-  - 1.9.3
   - 2.0.0
   - 2.1
   - 2.2
-  - jruby-19mode
-  - jruby-head
-  - rbx-2
-  - ruby-head
+  - 2.3.0
+  - 2.4.0
+  - jruby-9.1.6.0
 matrix:
-  allow_failures:
-    - rvm: jruby-head
-    - rvm: ruby-head
   fast_finish: true
 sudo: false
diff --git a/Gemfile b/Gemfile
index 39bc30f..e9e2b0a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ group :test do
   gem "coveralls"
   gem "rspec",      "~> 3.1"
   gem "simplecov",  ">= 0.9"
-  gem "rubocop",    "~> 0.28.0"
+  gem "rubocop",    "= 0.40.0"
 end
 
 group :doc do
diff --git a/README.md b/README.md
index f795042..ccbc2e7 100644
--- a/README.md
+++ b/README.md
@@ -50,10 +50,11 @@ socket << form.to_s
 This library aims to support and is [tested against][ci] the following Ruby
 versions:
 
-* Ruby 1.9.3
 * Ruby 2.0.0
 * Ruby 2.1.x
 * Ruby 2.2.x
+* Ruby 2.3.x
+* JRuby 9.1.6.0
 
 If something doesn't work on one of these versions, it's a bug.
 
diff --git a/appveyor.yml b/appveyor.yml
new file mode 100644
index 0000000..900265c
--- /dev/null
+++ b/appveyor.yml
@@ -0,0 +1,10 @@
+version: "#{build}"
+build: off
+init:
+  - git config --global core.autocrlf true
+install:
+  - set PATH=C:\Ruby23\bin;%PATH%
+  - bundle install
+test_script:
+  - bundle exec rake
+skip_tags: true
diff --git a/http-form_data.gemspec b/http-form_data.gemspec
index dada111..bb24696 100644
--- a/http-form_data.gemspec
+++ b/http-form_data.gemspec
@@ -11,15 +11,15 @@ Gem::Specification.new do |spec|
   spec.email         = ["ixti@member.fsf.org"]
   spec.license       = "MIT"
   spec.summary       = "http-form_data-#{HTTP::FormData::VERSION}"
-  spec.description   = <<-DESC.gsub(/^\s+> /m, "").gsub("\n", " ").strip
+  spec.description   = <<-DESC.gsub(/^\s+> /m, "").tr("\n", " ").strip
   > Utility-belt to build form data request bodies.
   > Provides support for `application/x-www-form-urlencoded` and
   > `multipart/form-data` types.
   DESC
 
   spec.files         = `git ls-files -z`.split("\x0")
-  spec.executables   = spec.files.grep(/^bin\//).map { |f| File.basename(f) }
-  spec.test_files    = spec.files.grep(/^(test|spec|features)\//)
+  spec.executables   = spec.files.grep(%r{^bin\/}).map { |f| File.basename(f) }
+  spec.test_files    = spec.files.grep(%r{^(test|spec|features)\/})
   spec.require_paths = ["lib"]
 
   spec.add_development_dependency "bundler", "~> 1.7"
diff --git a/lib/http/form_data.rb b/lib/http/form_data.rb
index c2853b5..9179a30 100644
--- a/lib/http/form_data.rb
+++ b/lib/http/form_data.rb
@@ -55,7 +55,7 @@ def ensure_hash(obj)
         when obj.nil?               then {}
         when obj.is_a?(Hash)        then obj
         when obj.respond_to?(:to_h) then obj.to_h
-        else fail Error, "#{obj.inspect} is neither Hash nor responds to :to_h"
+        else raise Error, "#{obj.inspect} is neither Hash nor responds to :to_h"
         end
       end
 
diff --git a/lib/http/form_data/file.rb b/lib/http/form_data/file.rb
index 2e00519..900eddc 100644
--- a/lib/http/form_data/file.rb
+++ b/lib/http/form_data/file.rb
@@ -67,7 +67,7 @@ def with_io
         if @file_or_io.is_a?(::File) || @file_or_io.is_a?(StringIO)
           yield @file_or_io
         else
-          ::File.open(@file_or_io) { |io| yield io }
+          ::File.open(@file_or_io, "rb") { |io| yield io }
         end
       end
     end
diff --git a/lib/http/form_data/multipart/param.rb b/lib/http/form_data/multipart/param.rb
index e84342a..a8617de 100644
--- a/lib/http/form_data/multipart/param.rb
+++ b/lib/http/form_data/multipart/param.rb
@@ -6,7 +6,8 @@ class Param
         # @param [#to_s] name
         # @param [FormData::File, #to_s] value
         def initialize(name, value)
-          @name, @value = name.to_s, value
+          @name = name.to_s
+          @value = value
 
           @header = "Content-Disposition: form-data; name=#{@name.inspect}"
 
diff --git a/lib/http/form_data/version.rb b/lib/http/form_data/version.rb
index 4953957..b2bf8cc 100644
--- a/lib/http/form_data/version.rb
+++ b/lib/http/form_data/version.rb
@@ -1,6 +1,6 @@
 module HTTP
   module FormData
     # Gem version.
-    VERSION = "1.0.1"
+    VERSION = "1.0.1".freeze
   end
 end
diff --git a/spec/lib/http/form_data/file_spec.rb b/spec/lib/http/form_data/file_spec.rb
index 37dfe1e..8dd5cee 100644
--- a/spec/lib/http/form_data/file_spec.rb
+++ b/spec/lib/http/form_data/file_spec.rb
@@ -28,7 +28,7 @@
 
     context "when file given as a String" do
       let(:file) { fixture("the-http-gem.info").to_s }
-      it { is_expected.to eq fixture("the-http-gem.info").read }
+      it { is_expected.to eq fixture("the-http-gem.info").read(:mode => "rb") }
     end
 
     context "when file given as StringIO" do
@@ -37,9 +37,9 @@
     end
 
     context "when file given as File" do
-      let(:file) { fixture("the-http-gem.info").open }
+      let(:file) { fixture("the-http-gem.info").open("rb") }
       after { file.close }
-      it { is_expected.to eq fixture("the-http-gem.info").read }
+      it { is_expected.to eq fixture("the-http-gem.info").read(:mode => "rb") }
     end
   end
 
diff --git a/spec/lib/http/form_data/multipart_spec.rb b/spec/lib/http/form_data/multipart_spec.rb
index b715541..de7176a 100644
--- a/spec/lib/http/form_data/multipart_spec.rb
+++ b/spec/lib/http/form_data/multipart_spec.rb
@@ -6,7 +6,10 @@
 
   describe "#content_type" do
     subject { form_data.content_type }
-    it { is_expected.to match(/^multipart\/form-data; boundary=#{boundary}$/) }
+
+    let(:content_type) { %r{^multipart\/form-data; boundary=#{boundary}$} }
+
+    it { is_expected.to match(content_type) }
   end
 
   describe "#content_length" do