diff --git a/.gitignore b/.gitignore
index feb18620..c7bac795 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,4 +15,5 @@ lib/libv8/VERSION
 /release/**/.scaleway
 /vendor/.gclient
 /vendor/.gclient_entries
+/vendor/.cipd
 /vendor/v8/
diff --git a/.travis.yml b/.travis.yml
index 42a4f668..727b14eb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,10 +7,12 @@ rvm:
   - 2.5
 matrix:
   include:
-    - rvm: 2.6
-      os: osx
-      osx_image: xcode9.4.1
-  fast_finish: true
+    - os: osx
+      osx_image: xcode12
+    - os: osx
+      osx_image: xcode11.3
+    - os: osx
+      osx_image: xcode10.1
 addons:
   apt:
     packages:
@@ -26,18 +28,22 @@ before_install:
 script:
   - git submodule update --init
   - bundle exec rake spec binary --trace
+before_deploy:
+  - bundle exec rake osx_varients --trace
 deploy:
   provider: releases
-  file: $(git ls-files -o pkg | head -1)
+  file_glob: true
+  file: pkg/*.gem
   api_key:
     secure: OMCBceg89uRnU+FIPAPbeOK2pISvV4Cz62r9iTRIGXQCOOXX8M40i77/3DmtkMtc9FEuNyAu1+CH886PL2WtZZPK4CmEU3HuqXz1a5VsCI+zcAZL1tevKvblXOVQ3MG+B/SZRC3rEzGwjk4027WtzCCGoGCLUu4TFJP05+/8XN4=
   skip_cleanup: true
   on:
     tags: true
-    # condition: $TRAVIS_OS_NAME = osx
+    rvm: '2.7' # Only deploy 1 of each platform
 cache:
   bundler: true
 notifications:
   recipients:
     - cowboyd@thefrontside.net
     - bordjukov@gmail.com
+    - nightpool@cybre.space
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 81597410..b5c43c03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+### v8.4.255.0 - 2020-07-15
+
+* Update upstream v8 version to 8.4.255.0
+
 ### v7.3.495.0 - 2020-04-14
 
 * Update upstream v8 version to 7.3.495.0
diff --git a/README.md b/README.md
index 308622bd..32e7eac4 100644
--- a/README.md
+++ b/README.md
@@ -26,9 +26,6 @@ platforms.
 * x86_64-darwin-19
 * x86_64-darwin-18
 * x86_64-darwin-17
-* x86_64-darwin-16
-* x86_64-darwin-15
-* x86_64-darwin-14
 * x86_64-linux
 * x86-linux
 
diff --git a/Rakefile b/Rakefile
index 44c6b408..a58bceab 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,6 +1,7 @@
 require 'bundler/setup'
 require 'rspec/core/rake_task'
 require 'tmpdir'
+require 'rubygems/package'
 
 Bundler::GemHelper.install_tasks
 RSpec::Core::RakeTask.new :spec
@@ -20,9 +21,20 @@ DISTRIBUTIONS = [
 module Helpers
   module_function
   def binary_gemspec(platform = Gem::Platform.local)
-    gemspec = eval(File.read 'libv8.gemspec')
-    gemspec.platform = platform
-    gemspec
+    eval(File.read 'libv8.gemspec').tap do |gemspec|
+      gemspec.platform = platform
+      gemspec.extensions.clear
+
+      # We don't need most things for the binary
+      gemspec.files = []
+      gemspec.files += ['lib/libv8.rb', 'lib/libv8/version.rb']
+      gemspec.files += ['ext/libv8/location.rb', 'ext/libv8/paths.rb']
+      gemspec.files += ['ext/libv8/.location.yml']
+
+      # V8
+      gemspec.files += Dir['vendor/v8/include/**/*.h']
+      gemspec.files += Dir['vendor/v8/out.gn/**/*.a']
+    end
   end
 
   def binary_gem_name(platform = Gem::Platform.local)
@@ -38,28 +50,11 @@ end
 desc "build a binary gem #{Helpers.binary_gem_name}"
 task :binary => :compile do
   gemspec = Helpers.binary_gemspec
-  gemspec.extensions.clear
-
-  # We don't need most things for the binary
-  gemspec.files = []
-  gemspec.files += ['lib/libv8.rb', 'lib/libv8/version.rb']
-  gemspec.files += ['ext/libv8/location.rb', 'ext/libv8/paths.rb']
-  gemspec.files += ['ext/libv8/.location.yml']
-
-  # V8
-  gemspec.files += Dir['vendor/v8/include/**/*.h']
-  gemspec.files += Dir['vendor/v8/out.gn/**/*.a']
 
   FileUtils.chmod 0644, gemspec.files
   FileUtils.mkdir_p 'pkg'
 
-  package = if Gem::VERSION < '2.0.0'
-    Gem::Builder.new(gemspec).build
-  else
-    require 'rubygems/package'
-    Gem::Package.build gemspec
-  end
-
+  package = Gem::Package.build gemspec
   FileUtils.mv package, 'pkg'
 end
 
@@ -110,22 +105,19 @@ end
 task :default => [:compile, :spec]
 task :build => [:clean]
 
-task :repack, [:gemfile, :new_arch] do |t, args|
-  dir = Dir::mktmpdir
-
-  begin
-    sh "gem unpack #{args[:gemfile]} --target=#{dir}"
-    sh "gem spec #{args[:gemfile]} --ruby > #{dir}/repack.gemspec"
-    Dir.chdir(dir) do
-      sh "sed -iorig 's/^  s.platform = .*$/  s.platform = \"#{args[:new_arch]}\".freeze/' repack.gemspec"
-      Dir.chdir(Dir.glob("libv8-*/").first) do
-        sh 'mv ../repack.gemspec ./'
-        sh 'gem build repack.gemspec'
-      end
-    end
+desc 'Generate OSX varient platform names. Requires `compile` to already have been run.'
+task :osx_varients do
+  gemspec = Helpers.binary_gemspec
+  next unless gemspec.platform.os == 'osx'
+
+  %w(x86_64 universal).each do |cpu|
+    platform = gemspec.platform.dup
+    next unless platform.cpu != cpu
+
+    platform.cpu = cpu
+    gemspec.platform = platform
 
-    sh "mv #{dir}/*/*.gem ./pkg/"
-  ensure
-    FileUtils.remove_entry_secure dir
+    package = Gem::Package.build gemspec
+    FileUtils.mv package, 'pkg'
   end
 end
diff --git a/ext/libv8/builder.rb b/ext/libv8/builder.rb
index 88716d55..7836f5e5 100644
--- a/ext/libv8/builder.rb
+++ b/ext/libv8/builder.rb
@@ -23,7 +23,8 @@ def gn_args
          v8_use_external_startup_data=false
          target_cpu="#{libv8_arch}"
          v8_target_cpu="#{libv8_arch}"
-         treat_warnings_as_errors=false).join(' ')
+         treat_warnings_as_errors=false
+         icu_use_data_file=false).join(' ')
     end
 
     def generate_gn_args
diff --git a/lib/libv8/version.rb b/lib/libv8/version.rb
index 54025723..62cee7b5 100644
--- a/lib/libv8/version.rb
+++ b/lib/libv8/version.rb
@@ -1,3 +1,3 @@
 module Libv8
-  VERSION = "7.3.495.0"
+  VERSION = "8.4.255.0"
 end
diff --git a/vendor/depot_tools b/vendor/depot_tools
index 9c062012..9d9199a5 160000
--- a/vendor/depot_tools
+++ b/vendor/depot_tools
@@ -1 +1 @@
-Subproject commit 9c0620120980e4c247ff8325ee8bbdcd4d9576e0
+Subproject commit 9d9199a509bf792d7d24ac91d92ed0d111f8d9fb