diff --git a/.github/workflows/bundler.yml b/.github/workflows/bundler.yml
index 7ea6be4aec21..223316c9d47e 100644
--- a/.github/workflows/bundler.yml
+++ b/.github/workflows/bundler.yml
@@ -30,23 +30,29 @@ jobs:
 
         ruby:
           - { name: ruby-3.2, value: 3.2.9 }
-          - { name: ruby-3.3, value: 3.3.9 }
-          - { name: ruby-3.4, value: 3.4.5 }
+          - { name: ruby-3.3, value: 3.3.10 }
+          - { name: ruby-3.4, value: 3.4.8 }
+          - { name: ruby-4.0, value: 4.0.0 }
 
         include:
           - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.2, value: 3.2.9 }, timeout: 90 }
-          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.3, value: 3.3.9 }, timeout: 90 }
-          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.4, value: 3.4.5 }, timeout: 90 }
+          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.3, value: 3.3.10 }, timeout: 90 }
+          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.4, value: 3.4.8 }, timeout: 90 }
+          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-4.0, value: 4.0.0 }, timeout: 90 }
 
           # Ruby 3.2 is about 20 minutes slower than 3.3/3.4, so it will be excluded from testing.
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.9 }, timeout: 150, group: a }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.9 }, timeout: 150, group: b }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.9 }, timeout: 150, group: c }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.9 }, timeout: 150, group: d }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.5 }, timeout: 150, group: a }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.5 }, timeout: 150, group: b }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.5 }, timeout: 150, group: c }
-          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.5 }, timeout: 150, group: d }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.10 }, timeout: 150, group: a }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.10 }, timeout: 150, group: b }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.10 }, timeout: 150, group: c }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.3, value: 3.3.10 }, timeout: 150, group: d }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.8 }, timeout: 150, group: a }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.8 }, timeout: 150, group: b }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.8 }, timeout: 150, group: c }
+          - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-3.4, value: 3.4.8 }, timeout: 150, group: d }
+          # - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-4.0, value: 4.0.0 }, timeout: 150, group: a }
+          # - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-4.0, value: 4.0.0 }, timeout: 150, group: b }
+          # - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-4.0, value: 4.0.0 }, timeout: 150, group: c }
+          # - { os: { name: Windows, value: windows-2025 }, ruby: { name: ruby-4.0, value: 4.0.0 }, timeout: 150, group: d }
 
           - { os: { name: Ubuntu, value: ubuntu-24.04 }, ruby: { name: jruby, value: jruby-10.0.2.0 } }
           - { os: { name: Windows, value: windows-2025 }, ruby: { name: jruby, value: jruby-10.0.2.0 } }
@@ -59,7 +65,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
diff --git a/.github/workflows/daily-bundler.yml b/.github/workflows/daily-bundler.yml
index 14f78a83c661..a45e980f666d 100644
--- a/.github/workflows/daily-bundler.yml
+++ b/.github/workflows/daily-bundler.yml
@@ -25,7 +25,7 @@ jobs:
           persist-credentials: false
 
       - name: Set up Ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ruby-head
           bundler: none
diff --git a/.github/workflows/daily-rubygems.yml b/.github/workflows/daily-rubygems.yml
index e7512f869f03..cbc16ec76665 100644
--- a/.github/workflows/daily-rubygems.yml
+++ b/.github/workflows/daily-rubygems.yml
@@ -28,7 +28,7 @@ jobs:
           persist-credentials: false
 
       - name: Set up Ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby }}
           bundler: none
diff --git a/.github/workflows/install-rubygems.yml b/.github/workflows/install-rubygems.yml
index fee2d0f0d247..d5a46f230deb 100644
--- a/.github/workflows/install-rubygems.yml
+++ b/.github/workflows/install-rubygems.yml
@@ -35,7 +35,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
@@ -128,7 +128,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
@@ -170,7 +170,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup original ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: 3.2
           bundler: none
@@ -191,7 +191,7 @@ jobs:
           GEM_HOME: bar
           GEM_PATH: bar
       - name: Setup final ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: 3.3
           bundler: none
@@ -220,7 +220,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
diff --git a/.github/workflows/realworld-bundler.yml b/.github/workflows/realworld-bundler.yml
index 7447bf59c3c6..39627df46a58 100644
--- a/.github/workflows/realworld-bundler.yml
+++ b/.github/workflows/realworld-bundler.yml
@@ -26,13 +26,15 @@ jobs:
 
         ruby:
           - { name: ruby-3.2, value: 3.2.9 }
-          - { name: ruby-3.3, value: 3.3.9 }
-          - { name: ruby-3.4, value: 3.4.5 }
+          - { name: ruby-3.3, value: 3.3.10 }
+          - { name: ruby-3.4, value: 3.4.8 }
+          - { name: ruby-4.0, value: 4.0.0 }
 
         include:
           - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.2, value: 3.2.9 } }
-          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.3, value: 3.3.9 } }
-          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.4, value: 3.4.5 } }
+          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.3, value: 3.3.10 } }
+          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-3.4, value: 3.4.8 } }
+          - { os: { name: macOS, value: macos-15 }, ruby: { name: ruby-4.0, value: 4.0.0 } }
     env:
       RGV: ..
       RUBYOPT: --disable-gems
@@ -41,7 +43,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
@@ -64,9 +66,9 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
-          ruby-version: 3.4.5
+          ruby-version: 3.4.8
           bundler: none
       - name: Prepare tapioca
         run: ../../../../bin/bundle install
@@ -91,7 +93,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
@@ -115,9 +117,9 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
-          ruby-version: 3.4.5
+          ruby-version: 3.4.8
           bundler: none
       - name: Prepare dependencies
         run: bin/rake setup
diff --git a/.github/workflows/rubygems.yml b/.github/workflows/rubygems.yml
index 90a920bc3cb8..f37377877d3e 100644
--- a/.github/workflows/rubygems.yml
+++ b/.github/workflows/rubygems.yml
@@ -28,8 +28,9 @@ jobs:
 
         ruby:
           - { name: "3.2", value: 3.2.9 }
-          - { name: "3.3", value: 3.3.9 }
-          - { name: "3.4", value: 3.4.5 }
+          - { name: "3.3", value: 3.3.10 }
+          - { name: "3.4", value: 3.4.8 }
+          - { name: "4.0", value: 4.0.0 }
 
         include:
           - ruby: { name: jruby, value: jruby-10.0.2.0 }
@@ -43,7 +44,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
diff --git a/.github/workflows/system-rubygems-bundler.yml b/.github/workflows/system-rubygems-bundler.yml
index 50b717431324..a6c7f77e8a1e 100644
--- a/.github/workflows/system-rubygems-bundler.yml
+++ b/.github/workflows/system-rubygems-bundler.yml
@@ -37,7 +37,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
diff --git a/.github/workflows/truffleruby-bundler.yml b/.github/workflows/truffleruby-bundler.yml
index c7715071150d..3f7bb03c96da 100644
--- a/.github/workflows/truffleruby-bundler.yml
+++ b/.github/workflows/truffleruby-bundler.yml
@@ -28,7 +28,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: truffleruby-24.2.1
           bundler: none
diff --git a/.github/workflows/ubuntu-lint.yml b/.github/workflows/ubuntu-lint.yml
index 0dda6a140eeb..01bf7721ec13 100644
--- a/.github/workflows/ubuntu-lint.yml
+++ b/.github/workflows/ubuntu-lint.yml
@@ -75,7 +75,7 @@ jobs:
         with:
           persist-credentials: false
       - name: Setup ruby
-        uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
+        uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
         with:
           ruby-version: ${{ matrix.ruby.value }}
           bundler: none
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2357165cef8d..b620d2ecde44 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,18 @@
 # Changelog
 
+## 4.0.4 / 2026-01-15
+
+### Enhancements:
+
+* Remove date require from rebuild command. Pull request
+  [#9232](https://github.com/ruby/rubygems/pull/9232) by jeremyevans
+* Installs bundler 4.0.4 as a default gem.
+
+### Bug fixes:
+
+* Add a missing "require 'etc'" statement:. Pull request
+  [#9242](https://github.com/ruby/rubygems/pull/9242) by Edouard-chin
+
 ## 4.0.3 / 2025-12-23
 
 ### Enhancements:
diff --git a/bundler/CHANGELOG.md b/bundler/CHANGELOG.md
index df09a5ba07ca..fee83430ea53 100644
--- a/bundler/CHANGELOG.md
+++ b/bundler/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Changelog
 
+## 4.0.4 (2026-01-15)
+
+### Enhancements:
+
+  - Validate more options for add sub-command [#5905](https://github.com/ruby/rubygems/pull/5905)
+  - Support Ruby 4.1 [#9219](https://github.com/ruby/rubygems/pull/9219)
+
+### Bug fixes:
+
+  - Fix dependency source bug in bundler [#9213](https://github.com/ruby/rubygems/pull/9213)
+  - Retain current bundler version on `bundle clean` [#9221](https://github.com/ruby/rubygems/pull/9221)
+
 ## 4.0.3 (2025-12-23)
 
 ### Enhancements:
diff --git a/bundler/lib/bundler/cli/add.rb b/bundler/lib/bundler/cli/add.rb
index 12a681a81688..9f1760409617 100644
--- a/bundler/lib/bundler/cli/add.rb
+++ b/bundler/lib/bundler/cli/add.rb
@@ -36,6 +36,16 @@ def inject_dependencies
     end
 
     def validate_options!
+      raise InvalidOption, "You cannot specify `--git` and `--github` at the same time." if options["git"] && options["github"]
+
+      unless options["git"] || options["github"]
+        raise InvalidOption, "You cannot specify `--branch` unless `--git` or `--github` is specified." if options["branch"]
+
+        raise InvalidOption, "You cannot specify `--ref` unless `--git` or `--github` is specified." if options["ref"]
+      end
+
+      raise InvalidOption, "You cannot specify `--branch` and `--ref` at the same time." if options["branch"] && options["ref"]
+
       raise InvalidOption, "You cannot specify `--strict` and `--optimistic` at the same time." if options[:strict] && options[:optimistic]
 
       # raise error when no gems are specified
diff --git a/bundler/lib/bundler/current_ruby.rb b/bundler/lib/bundler/current_ruby.rb
index ab6520a106a4..17c7655adb58 100644
--- a/bundler/lib/bundler/current_ruby.rb
+++ b/bundler/lib/bundler/current_ruby.rb
@@ -11,7 +11,7 @@ def self.current_ruby
   end
 
   class CurrentRuby
-    ALL_RUBY_VERSIONS = [*18..27, *30..34, 40].freeze
+    ALL_RUBY_VERSIONS = [*18..27, *30..34, *40..41].freeze
     KNOWN_MINOR_VERSIONS = ALL_RUBY_VERSIONS.map {|v| v.digits.reverse.join(".") }.freeze
     KNOWN_MAJOR_VERSIONS = ALL_RUBY_VERSIONS.map {|v| v.digits.last.to_s }.uniq.freeze
     PLATFORM_MAP = {
diff --git a/bundler/lib/bundler/definition.rb b/bundler/lib/bundler/definition.rb
index 2fa7d0d27794..5ab577f504c3 100644
--- a/bundler/lib/bundler/definition.rb
+++ b/bundler/lib/bundler/definition.rb
@@ -1066,7 +1066,22 @@ def converge_specs(specs)
 
           deps << dep if !replacement_source || lockfile_source.include?(replacement_source) || new_deps.include?(dep)
         else
-          replacement_source = sources.get(lockfile_source)
+          parent_dep = @dependencies.find do |d|
+            next unless d.source && d.source != lockfile_source
+            next if d.source.is_a?(Source::Gemspec)
+
+            parent_locked_specs = @originally_locked_specs[d.name]
+
+            parent_locked_specs.any? do |parent_spec|
+              parent_spec.runtime_dependencies.any? {|rd| rd.name == s.name }
+            end
+          end
+
+          if parent_dep
+            replacement_source = parent_dep.source
+          else
+            replacement_source = sources.get(lockfile_source)
+          end
         end
 
         # Replace the locked dependency's source with the equivalent source from the Gemfile
diff --git a/bundler/lib/bundler/rubygems_integration.rb b/bundler/lib/bundler/rubygems_integration.rb
index d8f95cffb8fc..e04ef232592a 100644
--- a/bundler/lib/bundler/rubygems_integration.rb
+++ b/bundler/lib/bundler/rubygems_integration.rb
@@ -432,7 +432,7 @@ def default_specs
     end
 
     def find_bundler(version)
-      find_name("bundler").find {|s| s.version.to_s == version }
+      find_name("bundler").find {|s| s.version.to_s == version.to_s }
     end
 
     def find_name(name)
diff --git a/bundler/lib/bundler/runtime.rb b/bundler/lib/bundler/runtime.rb
index 5eb827dcb2a8..5280e72aa24b 100644
--- a/bundler/lib/bundler/runtime.rb
+++ b/bundler/lib/bundler/runtime.rb
@@ -174,7 +174,14 @@ def clean(dry_run = false)
       spec_cache_paths     = []
       spec_gemspec_paths   = []
       spec_extension_paths = []
-      Bundler.rubygems.add_default_gems_to(specs).values.each do |spec|
+      specs_to_keep = Bundler.rubygems.add_default_gems_to(specs).values
+
+      current_bundler = Bundler.rubygems.find_bundler(Bundler.gem_version)
+      if current_bundler
+        specs_to_keep << current_bundler
+      end
+
+      specs_to_keep.each do |spec|
         spec_gem_paths << spec.full_gem_path
         # need to check here in case gems are nested like for the rails git repo
         md = %r{(.+bundler/gems/.+-[a-f0-9]{7,12})}.match(spec.full_gem_path)
diff --git a/bundler/lib/bundler/version.rb b/bundler/lib/bundler/version.rb
index 732b4a05631e..8c039d16a06c 100644
--- a/bundler/lib/bundler/version.rb
+++ b/bundler/lib/bundler/version.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 
 module Bundler
-  VERSION = "4.0.3".freeze
+  VERSION = "4.0.4".freeze
 
   def self.bundler_major_version
     @bundler_major_version ||= gem_version.segments.first
diff --git a/bundler/spec/bundler/current_ruby_spec.rb b/bundler/spec/bundler/current_ruby_spec.rb
index aa19a4140765..79eb802aa522 100644
--- a/bundler/spec/bundler/current_ruby_spec.rb
+++ b/bundler/spec/bundler/current_ruby_spec.rb
@@ -23,6 +23,7 @@
         ruby_33: Gem::Platform::RUBY,
         ruby_34: Gem::Platform::RUBY,
         ruby_40: Gem::Platform::RUBY,
+        ruby_41: Gem::Platform::RUBY,
         mri: Gem::Platform::RUBY,
         mri_18: Gem::Platform::RUBY,
         mri_19: Gem::Platform::RUBY,
@@ -40,6 +41,7 @@
         mri_33: Gem::Platform::RUBY,
         mri_34: Gem::Platform::RUBY,
         mri_40: Gem::Platform::RUBY,
+        mri_41: Gem::Platform::RUBY,
         rbx: Gem::Platform::RUBY,
         truffleruby: Gem::Platform::RUBY,
         jruby: Gem::Platform::JAVA,
@@ -61,7 +63,8 @@
         windows_32: Gem::Platform::WINDOWS,
         windows_33: Gem::Platform::WINDOWS,
         windows_34: Gem::Platform::WINDOWS,
-        windows_40: Gem::Platform::WINDOWS }
+        windows_40: Gem::Platform::WINDOWS,
+        windows_41: Gem::Platform::WINDOWS }
     end
 
     let(:deprecated) do
@@ -82,6 +85,7 @@
         mswin_33: Gem::Platform::MSWIN,
         mswin_34: Gem::Platform::MSWIN,
         mswin_40: Gem::Platform::MSWIN,
+        mswin_41: Gem::Platform::MSWIN,
         mswin64: Gem::Platform::MSWIN64,
         mswin64_19: Gem::Platform::MSWIN64,
         mswin64_20: Gem::Platform::MSWIN64,
@@ -98,6 +102,7 @@
         mswin64_33: Gem::Platform::MSWIN64,
         mswin64_34: Gem::Platform::MSWIN64,
         mswin64_40: Gem::Platform::MSWIN64,
+        mswin64_41: Gem::Platform::MSWIN64,
         mingw: Gem::Platform::UNIVERSAL_MINGW,
         mingw_18: Gem::Platform::UNIVERSAL_MINGW,
         mingw_19: Gem::Platform::UNIVERSAL_MINGW,
@@ -115,6 +120,7 @@
         mingw_33: Gem::Platform::UNIVERSAL_MINGW,
         mingw_34: Gem::Platform::UNIVERSAL_MINGW,
         mingw_40: Gem::Platform::UNIVERSAL_MINGW,
+        mingw_41: Gem::Platform::UNIVERSAL_MINGW,
         x64_mingw: Gem::Platform::UNIVERSAL_MINGW,
         x64_mingw_20: Gem::Platform::UNIVERSAL_MINGW,
         x64_mingw_21: Gem::Platform::UNIVERSAL_MINGW,
@@ -129,7 +135,8 @@
         x64_mingw_32: Gem::Platform::UNIVERSAL_MINGW,
         x64_mingw_33: Gem::Platform::UNIVERSAL_MINGW,
         x64_mingw_34: Gem::Platform::UNIVERSAL_MINGW,
-        x64_mingw_40: Gem::Platform::UNIVERSAL_MINGW }
+        x64_mingw_40: Gem::Platform::UNIVERSAL_MINGW,
+        x64_mingw_41: Gem::Platform::UNIVERSAL_MINGW }
     end
     # rubocop:enable Naming/VariableNumber
 
diff --git a/bundler/spec/commands/add_spec.rb b/bundler/spec/commands/add_spec.rb
index 00aa6415e11c..ed98a914f326 100644
--- a/bundler/spec/commands/add_spec.rb
+++ b/bundler/spec/commands/add_spec.rb
@@ -236,6 +236,40 @@
     end
   end
 
+  describe "with mismatched pair in --git/--github, --branch/--ref" do
+    describe "with --git and --github" do
+      it "throws error" do
+        bundle "add 'foo' --git x --github y", raise_on_error: false
+
+        expect(err).to include("You cannot specify `--git` and `--github` at the same time.")
+      end
+    end
+
+    describe "with --branch and --ref with --git" do
+      it "throws error" do
+        bundle "add 'foo' --branch x --ref y --git file://git", raise_on_error: false
+
+        expect(err).to include("You cannot specify `--branch` and `--ref` at the same time.")
+      end
+    end
+
+    describe "with --branch but without --git or --github" do
+      it "throws error" do
+        bundle "add 'foo' --branch x", raise_on_error: false
+
+        expect(err).to include("You cannot specify `--branch` unless `--git` or `--github` is specified.")
+      end
+    end
+
+    describe "with --ref but without --git or --github" do
+      it "throws error" do
+        bundle "add 'foo' --ref y", raise_on_error: false
+
+        expect(err).to include("You cannot specify `--ref` unless `--git` or `--github` is specified.")
+      end
+    end
+  end
+
   describe "with --skip-install" do
     it "adds gem to Gemfile but is not installed" do
       bundle "add foo --skip-install --version=2.0"
diff --git a/bundler/spec/commands/clean_spec.rb b/bundler/spec/commands/clean_spec.rb
index 6b678d0aa545..793aacf5c2b5 100644
--- a/bundler/spec/commands/clean_spec.rb
+++ b/bundler/spec/commands/clean_spec.rb
@@ -898,4 +898,41 @@ def should_not_have_gems(*gems)
 
     expect(very_simple_binary_extensions_dir).to be_nil
   end
+
+  it "does not remove the bundler version currently running" do
+    gemfile <<-G
+      source "https://gem.repo1"
+
+      gem "myrack"
+    G
+
+    bundle "config set path vendor/bundle"
+    bundle "install"
+
+    version = Bundler.gem_version.to_s
+    # Simulate that the locked bundler version is installed in the bundle path
+    # by creating the gem directory and gemspec (as would happen after bundle install with that version)
+    Pathname(vendored_gems("cache/bundler-#{version}.gem")).tap do |path|
+      path.basename.mkpath
+      FileUtils.touch(path)
+    end
+    FileUtils.touch(vendored_gems("gems/bundler-#{version}"))
+    Pathname(vendored_gems("specifications/bundler-#{version}.gemspec")).tap do |path|
+      path.basename.mkpath
+      path.write(<<~GEMSPEC)
+        Gem::Specification.new do |s|
+          s.name = "bundler"
+          s.version = "#{version}"
+          s.authors = ["bundler team"]
+          s.summary = "The best way to manage your application's dependencies"
+        end
+      GEMSPEC
+    end
+
+    should_have_gems "bundler-#{version}"
+
+    bundle :clean
+
+    should_have_gems "bundler-#{version}"
+  end
 end
diff --git a/bundler/spec/install/gemfile/sources_spec.rb b/bundler/spec/install/gemfile/sources_spec.rb
index c0b4d98f1c5c..90f87ed0c5da 100644
--- a/bundler/spec/install/gemfile/sources_spec.rb
+++ b/bundler/spec/install/gemfile/sources_spec.rb
@@ -1079,4 +1079,120 @@
       expect(lockfile).to eq original_lockfile.gsub("bigdecimal (1.0.0)", "bigdecimal (3.3.1)")
     end
   end
+
+  context "when switching a gem with components from rubygems to git source" do
+    before do
+      build_repo2 do
+        build_gem "rails", "7.0.0" do |s|
+          s.add_dependency "actionpack", "7.0.0"
+          s.add_dependency "activerecord", "7.0.0"
+        end
+        build_gem "actionpack", "7.0.0"
+        build_gem "activerecord", "7.0.0"
+        # propshaft also depends on actionpack, creating the conflict
+        build_gem "propshaft", "1.0.0" do |s|
+          s.add_dependency "actionpack", ">= 7.0.0"
+        end
+      end
+
+      build_git "rails", "7.0.0", path: lib_path("rails") do |s|
+        s.add_dependency "actionpack", "7.0.0"
+        s.add_dependency "activerecord", "7.0.0"
+      end
+
+      build_git "actionpack", "7.0.0", path: lib_path("rails")
+      build_git "activerecord", "7.0.0", path: lib_path("rails")
+
+      install_gemfile <<-G
+        source "https://gem.repo2"
+        gem "rails", "7.0.0"
+        gem "propshaft"
+      G
+    end
+
+    it "moves component gems to the git source in the lockfile" do
+      expect(lockfile).to include("remote: https://gem.repo2")
+      expect(lockfile).to include("rails (7.0.0)")
+      expect(lockfile).to include("actionpack (7.0.0)")
+      expect(lockfile).to include("activerecord (7.0.0)")
+      expect(lockfile).to include("propshaft (1.0.0)")
+
+      gemfile <<-G
+        source "https://gem.repo2"
+        gem "rails", git: "#{lib_path("rails")}"
+        gem "propshaft"
+      G
+
+      bundle "install"
+
+      expect(lockfile).to include("remote: #{lib_path("rails")}")
+      expect(lockfile).to include("rails (7.0.0)")
+      expect(lockfile).to include("actionpack (7.0.0)")
+      expect(lockfile).to include("activerecord (7.0.0)")
+
+      # Component gems should NOT remain in the GEM section
+      # Extract just the GEM section by splitting on GIT first, then GEM
+      gem_section = lockfile.split("GEM\n").last.split(/\n(PLATFORMS|DEPENDENCIES)/)[0]
+      expect(gem_section).not_to include("actionpack (7.0.0)")
+      expect(gem_section).not_to include("activerecord (7.0.0)")
+    end
+  end
+
+  context "when switching a gem with components from rubygems to path source" do
+    before do
+      build_repo2 do
+        build_gem "rails", "7.0.0" do |s|
+          s.add_dependency "actionpack", "7.0.0"
+          s.add_dependency "activerecord", "7.0.0"
+        end
+        build_gem "actionpack", "7.0.0"
+        build_gem "activerecord", "7.0.0"
+        # propshaft also depends on actionpack, creating the conflict
+        build_gem "propshaft", "1.0.0" do |s|
+          s.add_dependency "actionpack", ">= 7.0.0"
+        end
+      end
+
+      build_lib "rails", "7.0.0", path: lib_path("rails") do |s|
+        s.add_dependency "actionpack", "7.0.0"
+        s.add_dependency "activerecord", "7.0.0"
+      end
+
+      build_lib "actionpack", "7.0.0", path: lib_path("rails")
+      build_lib "activerecord", "7.0.0", path: lib_path("rails")
+
+      install_gemfile <<-G
+        source "https://gem.repo2"
+        gem "rails", "7.0.0"
+        gem "propshaft"
+      G
+    end
+
+    it "moves component gems to the path source in the lockfile" do
+      expect(lockfile).to include("remote: https://gem.repo2")
+      expect(lockfile).to include("rails (7.0.0)")
+      expect(lockfile).to include("actionpack (7.0.0)")
+      expect(lockfile).to include("activerecord (7.0.0)")
+      expect(lockfile).to include("propshaft (1.0.0)")
+
+      gemfile <<-G
+        source "https://gem.repo2"
+        gem "rails", path: "#{lib_path("rails")}"
+        gem "propshaft"
+      G
+
+      bundle "install"
+
+      expect(lockfile).to include("remote: #{lib_path("rails")}")
+      expect(lockfile).to include("rails (7.0.0)")
+      expect(lockfile).to include("actionpack (7.0.0)")
+      expect(lockfile).to include("activerecord (7.0.0)")
+
+      # Component gems should NOT remain in the GEM section
+      # Extract just the GEM section by splitting appropriately
+      gem_section = lockfile.split("GEM\n").last.split(/\n(PLATFORMS|DEPENDENCIES)/)[0]
+      expect(gem_section).not_to include("actionpack (7.0.0)")
+      expect(gem_section).not_to include("activerecord (7.0.0)")
+    end
+  end
 end
diff --git a/bundler/spec/realworld/fixtures/tapioca/Gemfile.lock b/bundler/spec/realworld/fixtures/tapioca/Gemfile.lock
index 2db720a69f46..1d4eae8ffe0b 100644
--- a/bundler/spec/realworld/fixtures/tapioca/Gemfile.lock
+++ b/bundler/spec/realworld/fixtures/tapioca/Gemfile.lock
@@ -46,4 +46,4 @@ DEPENDENCIES
   tapioca
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/bundler/spec/realworld/fixtures/warbler/Gemfile.lock b/bundler/spec/realworld/fixtures/warbler/Gemfile.lock
index c37fbbb7eed5..6eb02db3db73 100644
--- a/bundler/spec/realworld/fixtures/warbler/Gemfile.lock
+++ b/bundler/spec/realworld/fixtures/warbler/Gemfile.lock
@@ -36,4 +36,4 @@ DEPENDENCIES
   warbler!
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/lib/rubygems.rb b/lib/rubygems.rb
index e99176fec0e1..9e90e608a50d 100644
--- a/lib/rubygems.rb
+++ b/lib/rubygems.rb
@@ -9,7 +9,7 @@
 require "rbconfig"
 
 module Gem
-  VERSION = "4.0.3"
+  VERSION = "4.0.4"
 end
 
 require_relative "rubygems/defaults"
diff --git a/lib/rubygems/commands/rebuild_command.rb b/lib/rubygems/commands/rebuild_command.rb
index 77a474ef1ddf..23b9d7b3ba92 100644
--- a/lib/rubygems/commands/rebuild_command.rb
+++ b/lib/rubygems/commands/rebuild_command.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "date"
 require "digest"
 require "fileutils"
 require "tmpdir"
diff --git a/lib/rubygems/installer.rb b/lib/rubygems/installer.rb
index 90aa25dc0728..914e41367731 100644
--- a/lib/rubygems/installer.rb
+++ b/lib/rubygems/installer.rb
@@ -943,7 +943,12 @@ def build_args
   end
 
   def build_jobs
-    @build_jobs ||= Etc.nprocessors + 1
+    @build_jobs ||= begin
+                      require "etc"
+                      Etc.nprocessors + 1
+                    rescue LoadError
+                      1
+                    end
   end
 
   def rb_config
diff --git a/test/rubygems/test_gem_commands_install_command.rb b/test/rubygems/test_gem_commands_install_command.rb
index 72ca9d826258..d2ca933a632c 100644
--- a/test/rubygems/test_gem_commands_install_command.rb
+++ b/test/rubygems/test_gem_commands_install_command.rb
@@ -1610,7 +1610,7 @@ def test_pass_down_the_job_option_to_make
 
     gem_make_out = File.read(File.join(gemspec.extension_dir, "gem_make.out"))
     if vc_windows? && nmake_found?
-      refute_includes(gem_make_out, "-j4")
+      refute_includes(gem_make_out, " -j4")
     else
       assert_includes(gem_make_out, "make -j4")
     end
diff --git a/test/rubygems/test_gem_commands_update_command.rb b/test/rubygems/test_gem_commands_update_command.rb
index 3bb4a72c4151..5ed12ad48140 100644
--- a/test/rubygems/test_gem_commands_update_command.rb
+++ b/test/rubygems/test_gem_commands_update_command.rb
@@ -722,7 +722,7 @@ def test_pass_down_the_job_option_to_make
 
     gem_make_out = File.read(File.join(gemspec.extension_dir, "gem_make.out"))
     if vc_windows? && nmake_found?
-      refute_includes(gem_make_out, "-j2")
+      refute_includes(gem_make_out, " -j2")
     else
       assert_includes(gem_make_out, "make -j2")
     end
diff --git a/tool/bundler/dev_gems.rb.lock b/tool/bundler/dev_gems.rb.lock
index fff9cfe70cb1..01317be72d11 100644
--- a/tool/bundler/dev_gems.rb.lock
+++ b/tool/bundler/dev_gems.rb.lock
@@ -129,4 +129,4 @@ CHECKSUMS
   turbo_tests (2.2.5) sha256=3fa31497d12976d11ccc298add29107b92bda94a90d8a0a5783f06f05102509f
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/tool/bundler/lint_gems.rb.lock b/tool/bundler/lint_gems.rb.lock
index 9d4823728151..7607c762d29d 100644
--- a/tool/bundler/lint_gems.rb.lock
+++ b/tool/bundler/lint_gems.rb.lock
@@ -119,4 +119,4 @@ CHECKSUMS
   wmi-lite (1.0.7) sha256=116ef5bb470dbe60f58c2db9047af3064c16245d6562c646bc0d90877e27ddda
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/tool/bundler/release_gems.rb.lock b/tool/bundler/release_gems.rb.lock
index 86a0df95c279..130079b4a621 100644
--- a/tool/bundler/release_gems.rb.lock
+++ b/tool/bundler/release_gems.rb.lock
@@ -87,4 +87,4 @@ CHECKSUMS
   uri (1.1.1) sha256=379fa58d27ffb1387eaada68c749d1426738bd0f654d812fcc07e7568f5c57c6
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/tool/bundler/rubocop_gems.rb.lock b/tool/bundler/rubocop_gems.rb.lock
index 70704bfc3889..a6d9fb125a5e 100644
--- a/tool/bundler/rubocop_gems.rb.lock
+++ b/tool/bundler/rubocop_gems.rb.lock
@@ -156,4 +156,4 @@ CHECKSUMS
   unicode-emoji (4.1.0) sha256=4997d2d5df1ed4252f4830a9b6e86f932e2013fbff2182a9ce9ccabda4f325a5
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/tool/bundler/standard_gems.rb.lock b/tool/bundler/standard_gems.rb.lock
index 669e5492a8a0..c4e2f1e78485 100644
--- a/tool/bundler/standard_gems.rb.lock
+++ b/tool/bundler/standard_gems.rb.lock
@@ -176,4 +176,4 @@ CHECKSUMS
   unicode-emoji (4.1.0) sha256=4997d2d5df1ed4252f4830a9b6e86f932e2013fbff2182a9ce9ccabda4f325a5
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/tool/bundler/test_gems.rb.lock b/tool/bundler/test_gems.rb.lock
index d8f7d7712284..46c12cfb6022 100644
--- a/tool/bundler/test_gems.rb.lock
+++ b/tool/bundler/test_gems.rb.lock
@@ -103,4 +103,4 @@ CHECKSUMS
   tilt (2.6.1) sha256=35a99bba2adf7c1e362f5b48f9b581cce4edfba98117e34696dde6d308d84770
 
 BUNDLED WITH
-  4.0.3
+  4.0.4
diff --git a/tool/bundler/vendor_gems.rb.lock b/tool/bundler/vendor_gems.rb.lock
index 19269bb5afab..8aef85935918 100644
--- a/tool/bundler/vendor_gems.rb.lock
+++ b/tool/bundler/vendor_gems.rb.lock
@@ -72,4 +72,4 @@ CHECKSUMS
   uri (1.1.1) sha256=379fa58d27ffb1387eaada68c749d1426738bd0f654d812fcc07e7568f5c57c6
 
 BUNDLED WITH
-  4.0.3
+  4.0.4