diff --git a/.github/workflows/build-gems.yml b/.github/workflows/build-gems.yml
index e134f1ef..f7fc4c24 100644
--- a/.github/workflows/build-gems.yml
+++ b/.github/workflows/build-gems.yml
@@ -74,7 +74,7 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
-          bundler-cache: false
+          bundler-cache: true
 
       - name: bundle install
         run: bundle install
@@ -127,8 +127,7 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3.4'
-          bundler-cache: false
+          bundler-cache: true
 
       - name: Download gem artifacts
         uses: actions/download-artifact@v4
diff --git a/.rubocop.yml b/.rubocop.yml
index 62881c7c..7cb06055 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -133,15 +133,7 @@ Metrics/PerceivedComplexity:
     - bin/**/*
 
 Layout/LineLength:
-  Max: 120
-  Exclude:
-    - test/**/*_test.rb
-    - lib/herb/token.rb
-    - lib/herb/ast/nodes.rb
-    - lib/herb/engine/error_formatter.rb
-    - lib/herb/engine/debug_visitor.rb
-    - lib/herb/engine/parser_error_overlay.rb
-    - lib/herb/engine/validation_error_overlay.rb
+  Enabled: false
 
 Layout/EmptyLines:
   Exclude:
@@ -183,3 +175,6 @@ Lint/UnderscorePrefixedVariableName:
 Lint/UnusedMethodArgument:
   Exclude:
     - lib/herb/errors.rb
+
+Style/IfUnlessModifier:
+  Enabled: false
diff --git a/.ruby-version b/.ruby-version
index 7921bd0c..fcdb2e10 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.4.8
+4.0.0
diff --git a/Gemfile b/Gemfile
index 2c505d9e..42a830aa 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,18 +7,23 @@ gemspec
 gem "prism", github: "ruby/prism", tag: "v1.7.0"
 
 gem "actionview", "~> 8.0"
+gem "digest", "~> 3.2"
 gem "erubi"
 gem "lz_string"
-gem "maxitest"
+gem "maxitest", "~> 6.0"
 gem "minitest-difftastic", "~> 0.2"
 gem "rake", "~> 13.2"
 gem "rake-compiler", "~> 1.3"
-gem "rake-compiler-dock", "1.11.0.rc1"
+gem "rake-compiler-dock", "~> 1.11"
+gem "rbs-inline", "~> 0.12"
 gem "reline", "~> 0.6"
 gem "rubocop", "~> 1.71"
+gem "sorbet"
+gem "steep", "~> 1.10"
 
-group :development do
-  gem "rbs-inline", "~> 0.12"
-  gem "sorbet"
-  gem "steep", "~> 1.10"
-end
+# TODO: remove once it's fixed in RBS
+# ❯ bundle exec rbs-inline --opt-out --output=sig/ lib/
+# /Users/marcoroth/Development/herb/vendor/bundle/ruby/4.0.0/gems/rbs-3.10.0/lib/rbs.rb:11: warning: tsort was loaded from the standard library, but will no longer be part of the default gems starting from Ruby 4.1.0
+# You can add tsort to your Gemfile or gemspec to silence this warning.
+# 🎉 Generated 0 RBS files under sig/
+gem "tsort", "~> 0.2.0"
diff --git a/Gemfile.lock b/Gemfile.lock
index 1ca494bb..2b69d912 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -48,18 +48,19 @@ GEM
       pretty_please
     difftastic (0.8.0-x86_64-linux)
       pretty_please
+    digest (3.2.1)
     dispersion (0.2.0)
       prism
     drb (2.2.3)
     erubi (1.13.1)
-    ffi (1.17.2-aarch64-linux-gnu)
-    ffi (1.17.2-aarch64-linux-musl)
-    ffi (1.17.2-arm64-darwin)
-    ffi (1.17.2-x86_64-darwin)
-    ffi (1.17.2-x86_64-linux-gnu)
-    ffi (1.17.2-x86_64-linux-musl)
+    ffi (1.17.3-aarch64-linux-gnu)
+    ffi (1.17.3-aarch64-linux-musl)
+    ffi (1.17.3-arm64-darwin)
+    ffi (1.17.3-x86_64-darwin)
+    ffi (1.17.3-x86_64-linux-gnu)
+    ffi (1.17.3-x86_64-linux-musl)
     fileutils (1.8.0)
-    i18n (1.14.7)
+    i18n (1.14.8)
       concurrent-ruby (~> 1.0)
     io-console (0.8.2)
     json (2.18.0)
@@ -73,23 +74,23 @@ GEM
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
     lz_string (0.3.0)
-    maxitest (6.1.0)
+    maxitest (6.2.0)
       minitest (>= 5.20.0, < 5.28.0)
     minitest (5.27.0)
     minitest-difftastic (0.2.1)
       difftastic (~> 0.6)
     mutex_m (0.3.0)
-    nokogiri (1.18.10-aarch64-linux-gnu)
+    nokogiri (1.19.0-aarch64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.18.10-aarch64-linux-musl)
+    nokogiri (1.19.0-aarch64-linux-musl)
       racc (~> 1.4)
-    nokogiri (1.18.10-arm64-darwin)
+    nokogiri (1.19.0-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.10-x86_64-darwin)
+    nokogiri (1.19.0-x86_64-darwin)
       racc (~> 1.4)
-    nokogiri (1.18.10-x86_64-linux-gnu)
+    nokogiri (1.19.0-x86_64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.18.10-x86_64-linux-musl)
+    nokogiri (1.19.0-x86_64-linux-musl)
       racc (~> 1.4)
     parallel (1.27.0)
     parser (3.3.10.0)
@@ -109,11 +110,11 @@ GEM
     rake (13.3.1)
     rake-compiler (1.3.1)
       rake
-    rake-compiler-dock (1.11.0.rc1)
+    rake-compiler-dock (1.11.1)
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rbs (3.9.5)
+    rbs (3.10.0)
       logger
     rbs-inline (0.12.0)
       prism (>= 0.29)
@@ -121,7 +122,7 @@ GEM
     regexp_parser (2.11.3)
     reline (0.6.3)
       io-console (~> 0.5)
-    rubocop (1.82.0)
+    rubocop (1.82.1)
       json (~> 2.3)
       language_server-protocol (~> 3.17.0.2)
       lint_roller (~> 1.1.0)
@@ -132,16 +133,16 @@ GEM
       rubocop-ast (>= 1.48.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 4.0)
-    rubocop-ast (1.48.0)
+    rubocop-ast (1.49.0)
       parser (>= 3.3.7.2)
-      prism (~> 1.4)
+      prism (~> 1.7)
     ruby-progressbar (1.13.0)
     securerandom (0.4.1)
-    sorbet (0.6.12865)
-      sorbet-static (= 0.6.12865)
-    sorbet-static (0.6.12865-aarch64-linux)
-    sorbet-static (0.6.12865-universal-darwin)
-    sorbet-static (0.6.12865-x86_64-linux)
+    sorbet (0.6.12872)
+      sorbet-static (= 0.6.12872)
+    sorbet-static (0.6.12872-aarch64-linux)
+    sorbet-static (0.6.12872-universal-darwin)
+    sorbet-static (0.6.12872-x86_64-linux)
     steep (1.10.0)
       activesupport (>= 5.1)
       concurrent-ruby (>= 1.1.10)
@@ -162,6 +163,7 @@ GEM
     strscan (3.1.6)
     terminal-table (4.0.0)
       unicode-display_width (>= 1.1.1, < 4)
+    tsort (0.2.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     unicode-display_width (3.2.0)
@@ -182,20 +184,22 @@ PLATFORMS
 
 DEPENDENCIES
   actionview (~> 8.0)
+  digest (~> 3.2)
   erubi
   herb!
   lz_string
-  maxitest
+  maxitest (~> 6.0)
   minitest-difftastic (~> 0.2)
   prism!
   rake (~> 13.2)
   rake-compiler (~> 1.3)
-  rake-compiler-dock (= 1.11.0.rc1)
+  rake-compiler-dock (~> 1.11)
   rbs-inline (~> 0.12)
   reline (~> 0.6)
   rubocop (~> 1.71)
   sorbet
   steep (~> 1.10)
+  tsort (~> 0.2.0)
 
 BUNDLED WITH
    2.7.2
diff --git a/ext/project.json b/ext/project.json
index f5911754..f28b07b9 100644
--- a/ext/project.json
+++ b/ext/project.json
@@ -21,7 +21,7 @@
     "test": {
       "executor": "nx:run-commands",
       "options": {
-        "command": "bundle exec mtest"
+        "command": "bundle exec rake test"
       },
       "dependsOn": ["ruby-gem:build"]
     }
diff --git a/test/snapshot_utils.rb b/test/snapshot_utils.rb
index 396e8134..28aaf380 100644
--- a/test/snapshot_utils.rb
+++ b/test/snapshot_utils.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require "fileutils"
-require "readline"
+require "reline"
 require "digest"
 require_relative "../bin/lib/compare_helpers"
 
@@ -155,7 +155,7 @@ def assert_snapshot_matches(actual, source, options = {})
 
         Run the test using UPDATE_SNAPSHOTS=true to update (or create) the snapshot file for "#{class_name} #{name}"
 
-        UPDATE_SNAPSHOTS=true mtest #{e.location}
+        UPDATE_SNAPSHOTS=true bundle exec minitest #{e.location}
 
         #{divider}
         \e[0m