diff --git a/.github/workflows/dart.yml b/.github/workflows/dart.yml
index 5f2711853..a23aee7a9 100644
--- a/.github/workflows/dart.yml
+++ b/.github/workflows/dart.yml
@@ -1,4 +1,4 @@
-# Created with package:mono_repo v6.5.7
+# Created with package:mono_repo v6.6.1
 name: Dart CI
 on:
   push:
@@ -36,7 +36,7 @@ jobs:
         name: Checkout repository
         uses: actions/checkout@93ea575cb5d8a053eaa0ac8fa3b40d7e05a33cc8
       - name: mono_repo self validate
-        run: dart pub global activate mono_repo 6.5.7
+        run: dart pub global activate mono_repo 6.6.1
       - name: mono_repo self validate
         run: dart pub global run mono_repo generate --validate
   job_002:
diff --git a/build_web_compilers/CHANGELOG.md b/build_web_compilers/CHANGELOG.md
index dbe0f20fc..d09d7ef39 100644
--- a/build_web_compilers/CHANGELOG.md
+++ b/build_web_compilers/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 4.0.7
+
+- Support `dart:js_interop_unsafe`.
+- Require Dart 3.1 or greater.
+
 ## 4.0.6
 
 - Allow version 3.3.x of the Dart SDK.
diff --git a/build_web_compilers/lib/src/platforms.dart b/build_web_compilers/lib/src/platforms.dart
index f96dcd425..c36a0a6b9 100644
--- a/build_web_compilers/lib/src/platforms.dart
+++ b/build_web_compilers/lib/src/platforms.dart
@@ -16,6 +16,7 @@ const _libraries = [
   'indexed_db',
   'js',
   'js_interop',
+  'js_interop_unsafe',
   'js_util',
   'math',
   'svg',
diff --git a/build_web_compilers/lib/src/web_entrypoint_builder.dart b/build_web_compilers/lib/src/web_entrypoint_builder.dart
index 9f5be8516..99f3a4e53 100644
--- a/build_web_compilers/lib/src/web_entrypoint_builder.dart
+++ b/build_web_compilers/lib/src/web_entrypoint_builder.dart
@@ -72,18 +72,12 @@ class WebEntrypointBuilder implements Builder {
         deprecatedOptions: _deprecatedOptions);
     var compilerOption =
         options.config[_compilerOption] as String? ?? 'dartdevc';
-    WebCompiler compiler;
-    switch (compilerOption) {
-      case 'dartdevc':
-        compiler = WebCompiler.DartDevc;
-        break;
-      case 'dart2js':
-        compiler = WebCompiler.Dart2Js;
-        break;
-      default:
-        throw ArgumentError.value(compilerOption, _compilerOption,
-            'Only `dartdevc` and `dart2js` are supported.');
-    }
+    var compiler = switch (compilerOption) {
+      'dartdevc' => WebCompiler.DartDevc,
+      'dart2js' => WebCompiler.Dart2Js,
+      _ => throw ArgumentError.value(compilerOption, _compilerOption,
+          'Only `dartdevc` and `dart2js` are supported.')
+    };
 
     if (options.config[_dart2jsArgsOption] is! List) {
       var message = options.config[_dart2jsArgsOption] is String
diff --git a/build_web_compilers/pubspec.yaml b/build_web_compilers/pubspec.yaml
index dc284d204..159792ad5 100644
--- a/build_web_compilers/pubspec.yaml
+++ b/build_web_compilers/pubspec.yaml
@@ -1,10 +1,10 @@
 name: build_web_compilers
-version: 4.0.6
+version: 4.0.7
 description: Builder implementations wrapping the dart2js and DDC compilers.
 repository: https://github.com/dart-lang/build/tree/master/build_web_compilers
 
 environment:
-  sdk: '>=3.0.0 <3.4.0'
+  sdk: '>=3.1.0 <3.4.0'
 
 dependencies:
   analyzer: '>=5.1.0 <7.0.0'
diff --git a/tool/ci.sh b/tool/ci.sh
index 2ce7d296a..3f9d41078 100755
--- a/tool/ci.sh
+++ b/tool/ci.sh
@@ -1,9 +1,10 @@
 #!/bin/bash
-# Created with package:mono_repo v6.5.7
+# Created with package:mono_repo v6.6.1
 
 # Support built in commands on windows out of the box.
+
 # When it is a flutter repo (check the pubspec.yaml for "sdk: flutter")
-# then "flutter" is called instead of "pub".
+# then "flutter pub" is called instead of "dart pub".
 # This assumes that the Flutter SDK has been installed in a previous step.
 function pub() {
   if grep -Fq "sdk: flutter" "${PWD}/pubspec.yaml"; then
@@ -12,18 +13,13 @@ function pub() {
     command dart pub "$@"
   fi
 }
-# When it is a flutter repo (check the pubspec.yaml for "sdk: flutter")
-# then "flutter" is called instead of "pub".
-# This assumes that the Flutter SDK has been installed in a previous step.
+
 function format() {
-  if grep -Fq "sdk: flutter" "${PWD}/pubspec.yaml"; then
-    command flutter format "$@"
-  else
-    command dart format "$@"
-  fi
+  command dart format "$@"
 }
+
 # When it is a flutter repo (check the pubspec.yaml for "sdk: flutter")
-# then "flutter" is called instead of "pub".
+# then "flutter analyze" is called instead of "dart analyze".
 # This assumes that the Flutter SDK has been installed in a previous step.
 function analyze() {
   if grep -Fq "sdk: flutter" "${PWD}/pubspec.yaml"; then