diff --git a/Library/Homebrew/cask/artifact/stage_only.rb b/Library/Homebrew/cask/artifact/stage_only.rb
index 3c5f10b639..e1c22e050a 100644
--- a/Library/Homebrew/cask/artifact/stage_only.rb
+++ b/Library/Homebrew/cask/artifact/stage_only.rb
@@ -11,8 +11,10 @@ module Cask
     class StageOnly < AbstractArtifact
       extend T::Sig
 
-      def self.from_args(cask, *args)
-        raise CaskInvalidError.new(cask.token, "'stage_only' takes only a single argument: true") if args != [true]
+      def self.from_args(cask, *args, **kwargs)
+        if args != [true] || kwargs.present?
+          raise CaskInvalidError.new(cask.token, "'stage_only' takes only a single argument: true")
+        end
 
         new(cask, true)
       end
diff --git a/Library/Homebrew/cask/artifact_set.rb b/Library/Homebrew/cask/artifact_set.rb
new file mode 100644
index 0000000000..de4817fddd
--- /dev/null
+++ b/Library/Homebrew/cask/artifact_set.rb
@@ -0,0 +1,22 @@
+# typed: false
+# frozen_string_literal: true
+
+require "set"
+
+module Cask
+  # Sorted set containing all cask artifacts.
+  #
+  # @api private
+  class ArtifactSet < ::Set
+    def each(&block)
+      return enum_for(__method__) { size } unless block
+
+      to_a.each(&block)
+      self
+    end
+
+    def to_a
+      super.sort
+    end
+  end
+end
diff --git a/Library/Homebrew/cask/cmd/abstract_command.rb b/Library/Homebrew/cask/cmd/abstract_command.rb
index 6c93a9e49f..6690ae55a3 100644
--- a/Library/Homebrew/cask/cmd/abstract_command.rb
+++ b/Library/Homebrew/cask/cmd/abstract_command.rb
@@ -33,8 +33,9 @@ module Cask
         Cmd.parser do
           instance_eval(&block) if block
 
-          OPTIONS.each do |option|
-            send(*option)
+          OPTIONS.map(&:dup).each do |option|
+            kwargs = option.pop
+            send(*option, **kwargs)
           end
         end
       end
diff --git a/Library/Homebrew/cask/cmd/install.rb b/Library/Homebrew/cask/cmd/install.rb
index 8b088de6b3..a52b412391 100644
--- a/Library/Homebrew/cask/cmd/install.rb
+++ b/Library/Homebrew/cask/cmd/install.rb
@@ -24,8 +24,9 @@ module Cask
           switch "--force",
                  description: "Force overwriting existing files."
 
-          OPTIONS.each do |option|
-            send(*option)
+          OPTIONS.map(&:dup).each do |option|
+            kwargs = option.pop
+            send(*option, **kwargs)
           end
 
           instance_eval(&block) if block
diff --git a/Library/Homebrew/cask/dsl.rb b/Library/Homebrew/cask/dsl.rb
index fc01a79f90..88556e2624 100644
--- a/Library/Homebrew/cask/dsl.rb
+++ b/Library/Homebrew/cask/dsl.rb
@@ -6,6 +6,7 @@ require "lazy_object"
 require "livecheck"
 
 require "cask/artifact"
+require "cask/artifact_set"
 
 require "cask/caskroom"
 require "cask/exceptions"
@@ -207,14 +208,14 @@ module Cask
     end
 
     # @api public
-    def appcast(*args)
-      set_unique_stanza(:appcast, args.empty?) { DSL::Appcast.new(*args) }
+    def appcast(*args, **kwargs)
+      set_unique_stanza(:appcast, args.empty? && kwargs.empty?) { DSL::Appcast.new(*args, **kwargs) }
     end
 
     # @api public
-    def container(*args)
-      set_unique_stanza(:container, args.empty?) do
-        DSL::Container.new(*args)
+    def container(**kwargs)
+      set_unique_stanza(:container, kwargs.empty?) do
+        DSL::Container.new(**kwargs)
       end
     end
 
@@ -261,12 +262,12 @@ module Cask
 
     # `depends_on` uses a load method so that multiple stanzas can be merged.
     # @api public
-    def depends_on(*args)
+    def depends_on(**kwargs)
       @depends_on ||= DSL::DependsOn.new
-      return @depends_on if args.empty?
+      return @depends_on if kwargs.empty?
 
       begin
-        @depends_on.load(*args)
+        @depends_on.load(**kwargs)
       rescue RuntimeError => e
         raise CaskInvalidError.new(cask, e)
       end
@@ -274,13 +275,13 @@ module Cask
     end
 
     # @api public
-    def conflicts_with(*args)
+    def conflicts_with(**kwargs)
       # TODO: remove this constraint, and instead merge multiple conflicts_with stanzas
-      set_unique_stanza(:conflicts_with, args.empty?) { DSL::ConflictsWith.new(*args) }
+      set_unique_stanza(:conflicts_with, kwargs.empty?) { DSL::ConflictsWith.new(**kwargs) }
     end
 
     def artifacts
-      @artifacts ||= SortedSet.new
+      @artifacts ||= ArtifactSet.new
     end
 
     def caskroom_path
@@ -337,13 +338,13 @@ module Cask
     end
 
     ORDINARY_ARTIFACT_CLASSES.each do |klass|
-      define_method(klass.dsl_key) do |*args|
+      define_method(klass.dsl_key) do |*args, **kwargs|
         if [*artifacts.map(&:class), klass].include?(Artifact::StageOnly) &&
            (artifacts.map(&:class) & ACTIVATABLE_ARTIFACT_CLASSES).any?
           raise CaskInvalidError.new(cask, "'stage_only' must be the only activatable artifact.")
         end
 
-        artifacts.add(klass.from_args(cask, *args))
+        artifacts.add(klass.from_args(cask, *args, **kwargs))
       rescue CaskInvalidError
         raise
       rescue => e
diff --git a/Library/Homebrew/cask/dsl/container.rb b/Library/Homebrew/cask/dsl/container.rb
index a386adab8d..4d0d63213a 100644
--- a/Library/Homebrew/cask/dsl/container.rb
+++ b/Library/Homebrew/cask/dsl/container.rb
@@ -16,7 +16,7 @@ module Cask
 
       attr_accessor(*VALID_KEYS, :pairs)
 
-      def initialize(pairs = {})
+      def initialize(**pairs)
         @pairs = pairs
         pairs.each do |key, value|
           raise "invalid container key: #{key.inspect}" unless VALID_KEYS.include?(key)
diff --git a/Library/Homebrew/cask/dsl/version.rb b/Library/Homebrew/cask/dsl/version.rb
index 6a643217fc..bb02439dbf 100644
--- a/Library/Homebrew/cask/dsl/version.rb
+++ b/Library/Homebrew/cask/dsl/version.rb
@@ -156,6 +156,12 @@ module Cask
         version { gsub(DIVIDER_REGEX, "") }
       end
 
+      # @api public
+      sig { params(separator: T.nilable(String)).returns(T.self_type) }
+      def chomp(separator = nil)
+        version { to_s.chomp(T.unsafe(separator)) }
+      end
+
       private
 
       sig { returns(T.self_type) }
diff --git a/Library/Homebrew/cli/parser.rb b/Library/Homebrew/cli/parser.rb
index a507451f25..68e3f1e24f 100644
--- a/Library/Homebrew/cli/parser.rb
+++ b/Library/Homebrew/cli/parser.rb
@@ -367,8 +367,9 @@ module Homebrew
       end
 
       def cask_options
-        self.class.global_cask_options.each do |method, *args, **options|
-          send(method, *args, **options)
+        self.class.global_cask_options.each do |args|
+          options = args.pop
+          send(*args, **options)
           conflicts "--formula", args.last
         end
         @cask_options = true
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index 60f2733cd1..f9eeb6a0b0 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -121,16 +121,18 @@ module Homebrew
         [:switch, "--overwrite", {
           description: "Delete files that already exist in the prefix while linking.",
         }],
-      ].each do |*args, **options|
+      ].each do |args|
+        options = args.pop
         send(*args, **options)
         conflicts "--cask", args.last
       end
       formula_options
       [
         [:switch, "--cask", "--casks", { description: "Treat all named arguments as casks." }],
-        *Cask::Cmd::AbstractCommand::OPTIONS,
-        *Cask::Cmd::Install::OPTIONS,
-      ].each do |*args, **options|
+        *Cask::Cmd::AbstractCommand::OPTIONS.map(&:dup),
+        *Cask::Cmd::Install::OPTIONS.map(&:dup),
+      ].each do |args|
+        options = args.pop
         send(*args, **options)
         conflicts "--formula", args.last
       end
diff --git a/Library/Homebrew/cmd/reinstall.rb b/Library/Homebrew/cmd/reinstall.rb
index 62f4777e0d..863f8162db 100644
--- a/Library/Homebrew/cmd/reinstall.rb
+++ b/Library/Homebrew/cmd/reinstall.rb
@@ -68,18 +68,20 @@ module Homebrew
         [:switch, "-g", "--git", {
           description: "Create a Git repository, useful for creating patches to the software.",
         }],
-      ].each do |options|
-        send(*options)
-        conflicts "--cask", options[-2]
+      ].each do |args|
+        options = args.pop
+        send(*args, **options)
+        conflicts "--cask", args.last
       end
       formula_options
       [
         [:switch, "--cask", "--casks", { description: "Treat all named arguments as casks." }],
-        *Cask::Cmd::AbstractCommand::OPTIONS,
-        *Cask::Cmd::Install::OPTIONS,
-      ].each do |options|
-        send(*options)
-        conflicts "--formula", options[-2]
+        *Cask::Cmd::AbstractCommand::OPTIONS.map(&:dup),
+        *Cask::Cmd::Install::OPTIONS.map(&:dup),
+      ].each do |args|
+        options = args.pop
+        send(*args, **options)
+        conflicts "--formula", args.last
       end
       cask_options
 
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index f176a26a5b..e33b3cab0b 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -76,9 +76,10 @@ module Homebrew
           env:         :display_install_times,
           description: "Print install times for each package at the end of the run.",
         }],
-      ].each do |options|
-        send(*options)
-        conflicts "--cask", options[-2]
+      ].each do |args|
+        options = args.pop
+        send(*args, **options)
+        conflicts "--cask", args.last
       end
       formula_options
       [
@@ -86,11 +87,12 @@ module Homebrew
           description: "Treat all named arguments as casks. If no named arguments " \
                        "are specified, upgrade only outdated casks.",
         }],
-        *Cask::Cmd::AbstractCommand::OPTIONS,
-        *Cask::Cmd::Upgrade::OPTIONS,
-      ].each do |options|
-        send(*options)
-        conflicts "--formula", options[-2]
+        *Cask::Cmd::AbstractCommand::OPTIONS.map(&:dup),
+        *Cask::Cmd::Upgrade::OPTIONS.map(&:dup),
+      ].each do |args|
+        options = args.pop
+        send(*args, **options)
+        conflicts "--formula", args.last
       end
       cask_options
 
diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 44815e7cd1..2c35aa08c4 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -594,7 +594,7 @@ class CurlGitHubPackagesDownloadStrategy < CurlDownloadStrategy
     # GitHub Packages authorization header.
     # HOMEBREW_GITHUB_PACKAGES_AUTH set in brew.sh
     meta[:headers] << "Authorization: #{HOMEBREW_GITHUB_PACKAGES_AUTH}"
-    super(url, name, version, meta)
+    super(url, name, version, **meta)
   end
 
   private
diff --git a/Library/Homebrew/software_spec.rb b/Library/Homebrew/software_spec.rb
index 29d1abfc54..df7353df8b 100644
--- a/Library/Homebrew/software_spec.rb
+++ b/Library/Homebrew/software_spec.rb
@@ -107,7 +107,7 @@ class SoftwareSpec
   def url(val = nil, specs = {})
     return @resource.url if val.nil?
 
-    @resource.url(val, specs)
+    @resource.url(val, **specs)
     dependency_collector.add(@resource)
   end
 
@@ -467,10 +467,11 @@ class Bottle
 
       image_name = GitHubPackages.image_formula_name(@name)
       image_tag = GitHubPackages.image_version_rebuild(version_rebuild)
-      resource.url("#{root_url}/#{image_name}/manifests/#{image_tag}", {
+      resource.url(
+        "#{root_url}/#{image_name}/manifests/#{image_tag}",
         using:   CurlGitHubPackagesDownloadStrategy,
         headers: ["Accept: application/vnd.oci.image.index.v1+json"],
-      })
+      )
       resource.downloader.resolved_basename = "#{name}-#{version_rebuild}.bottle_manifest.json"
       resource
     end
@@ -501,7 +502,7 @@ class Bottle
 
     filename = Filename.create(resource.owner, @tag, @spec.rebuild)
     path, resolved_basename = Utils::Bottles.path_resolved_basename(val, name, resource.checksum, filename)
-    @resource.url("#{val}/#{path}", select_download_strategy(specs))
+    @resource.url("#{val}/#{path}", **select_download_strategy(specs))
     @resource.downloader.resolved_basename = resolved_basename if resolved_basename.present?
   end
 end
diff --git a/Library/Homebrew/system_command.rb b/Library/Homebrew/system_command.rb
index 17ff585d10..2dca869746 100644
--- a/Library/Homebrew/system_command.rb
+++ b/Library/Homebrew/system_command.rb
@@ -24,12 +24,12 @@ class SystemCommand
   module Mixin
     extend T::Sig
 
-    def system_command(*args)
-      T.unsafe(SystemCommand).run(*args)
+    def system_command(executable, **options)
+      SystemCommand.run(executable, **options)
     end
 
-    def system_command!(*args)
-      T.unsafe(SystemCommand).run!(*args)
+    def system_command!(command, **options)
+      SystemCommand.run!(command, **options)
     end
   end
 
@@ -37,11 +37,11 @@ class SystemCommand
   extend Predicable
 
   def self.run(executable, **options)
-    T.unsafe(self).new(executable, **options).run!
+    new(executable, **options).run!
   end
 
   def self.run!(command, **options)
-    T.unsafe(self).run(command, **options, must_succeed: true)
+    run(command, **options, must_succeed: true)
   end
 
   sig { returns(SystemCommand::Result) }
diff --git a/Library/Homebrew/test/utils/user_spec.rb b/Library/Homebrew/test/utils/user_spec.rb
index b223b30ec6..610d6b4c8b 100644
--- a/Library/Homebrew/test/utils/user_spec.rb
+++ b/Library/Homebrew/test/utils/user_spec.rb
@@ -10,7 +10,7 @@ describe User do
 
   describe "#gui?" do
     before do
-      allow(SystemCommand).to receive(:run).with("who")
+      allow(SystemCommand).to receive(:run).with("who", {})
         .and_return([who_output, "", instance_double(Process::Status, success?: true)])
     end
 
diff --git a/Library/Homebrew/utils/gems.rb b/Library/Homebrew/utils/gems.rb
index 24b7c5bd90..7db328ef4a 100644
--- a/Library/Homebrew/utils/gems.rb
+++ b/Library/Homebrew/utils/gems.rb
@@ -119,6 +119,10 @@ module Homebrew
   end
 
   def install_bundler!
+    if Gem.ruby_version >= Gem::Version.new("2.7")
+      raise "Installing and using Bundler is currently only supported on Ruby 2.6."
+    end
+
     setup_gem_environment!(gem_home: gem_user_dir, gem_bindir: gem_user_bindir)
     install_gem_setup_path!(
       "bundler",