diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98816c1aa..aaa714056 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 2.0.0
+
+* **Breaking change:** The `@-moz-document` rule no longer has any special
+  parsing associated with it. It is now parsed like any other unknown plain CSS
+  at-rule, where Sass features are only allowed within `#{}` interpolation.
+
 ## 1.80.6
 
 ### Command-Line Interface
diff --git a/lib/src/deprecation.dart b/lib/src/deprecation.dart
index 3281e720d..c8b452576 100644
--- a/lib/src/deprecation.dart
+++ b/lib/src/deprecation.dart
@@ -15,7 +15,7 @@ enum Deprecation {
   // DO NOT EDIT. This section was generated from the language repo.
   // See tool/grind/generate_deprecations.dart for details.
   //
-  // Checksum: 47c97f7824eb25d7f1e64e3230938b88330d40b4
+  // Checksum: 651decb8bf8d0378b657241a5a0db7272c228fd4
 
   /// Deprecation for passing a string directly to meta.call().
   callString('call-string',
@@ -27,7 +27,9 @@ enum Deprecation {
 
   /// Deprecation for @-moz-document.
   mozDocument('moz-document',
-      deprecatedIn: '1.7.2', description: '@-moz-document.'),
+      deprecatedIn: '1.7.2',
+      obsoleteIn: '2.0.0',
+      description: '@-moz-document.'),
 
   /// Deprecation for imports using relative canonical URLs.
   relativeCanonical('relative-canonical',
@@ -175,9 +177,10 @@ enum Deprecation {
   Version? get obsoleteIn => _obsoleteIn?.andThen(Version.parse);
 
   /// Constructs a regular deprecation.
-  const Deprecation(this.id, {required String? deprecatedIn, this.description})
+  const Deprecation(this.id,
+      {required String? deprecatedIn, this.description, String? obsoleteIn})
       : _deprecatedIn = deprecatedIn,
-        _obsoleteIn = null,
+        _obsoleteIn = obsoleteIn,
         isFuture = false;
 
   /// Constructs a future deprecation.
diff --git a/lib/src/js/deprecations.dart b/lib/src/js/deprecations.dart
index e26fe9ea3..b88d2472a 100644
--- a/lib/src/js/deprecations.dart
+++ b/lib/src/js/deprecations.dart
@@ -42,7 +42,7 @@ final Map<String, Deprecation?> deprecations = {
               })(),
           description: deprecation.description,
           deprecatedIn: deprecation.deprecatedIn,
-          obsoleteIn: deprecation.deprecatedIn),
+          obsoleteIn: deprecation.obsoleteIn),
 };
 
 /// Parses a list of [deprecations] from JS into an list of Dart [Deprecation]
diff --git a/lib/src/parse/css.dart b/lib/src/parse/css.dart
index 4fd9ae2df..77bbc4f00 100644
--- a/lib/src/parse/css.dart
+++ b/lib/src/parse/css.dart
@@ -69,7 +69,6 @@ class CssParser extends ScssParser {
         _forbiddenAtRule(start),
       "import" => _cssImportRule(start),
       "media" => mediaRule(start),
-      "-moz-document" => mozDocumentRule(start, name),
       "supports" => supportsRule(start),
       _ => unknownAtRule(start, name)
     };
diff --git a/lib/src/parse/stylesheet.dart b/lib/src/parse/stylesheet.dart
index 94f551d2d..c2b1c6068 100644
--- a/lib/src/parse/stylesheet.dart
+++ b/lib/src/parse/stylesheet.dart
@@ -651,8 +651,6 @@ abstract class StylesheetParser extends Parser {
         return mediaRule(start);
       case "mixin":
         return _mixinRule(start);
-      case "-moz-document":
-        return mozDocumentRule(start, name);
       case "return":
         return _disallowedAtRule(start);
       case "supports":
@@ -1345,91 +1343,6 @@ abstract class StylesheetParser extends Parser {
     });
   }
 
-  /// Consumes a `@moz-document` rule.
-  ///
-  /// Gecko's `@-moz-document` diverges from [the specification][] allows the
-  /// `url-prefix` and `domain` functions to omit quotation marks, contrary to
-  /// the standard.
-  ///
-  /// [the specification]: http://www.w3.org/TR/css3-conditional/
-  @protected
-  AtRule mozDocumentRule(LineScannerState start, Interpolation name) {
-    var valueStart = scanner.state;
-    var buffer = InterpolationBuffer();
-    var needsDeprecationWarning = false;
-    while (true) {
-      if (scanner.peekChar() == $hash) {
-        var (expression, span) = singleInterpolation();
-        buffer.add(expression, span);
-        needsDeprecationWarning = true;
-      } else {
-        var identifierStart = scanner.state;
-        var identifier = this.identifier();
-        switch (identifier) {
-          case "url" || "url-prefix" || "domain":
-            if (_tryUrlContents(identifierStart, name: identifier)
-                case var contents?) {
-              buffer.addInterpolation(contents);
-            } else {
-              scanner.expectChar($lparen);
-              whitespace();
-              var argument = interpolatedString();
-              scanner.expectChar($rparen);
-
-              buffer
-                ..write(identifier)
-                ..writeCharCode($lparen)
-                ..addInterpolation(argument.asInterpolation())
-                ..writeCharCode($rparen);
-            }
-
-            // A url-prefix with no argument, or with an empty string as an
-            // argument, is not (yet) deprecated.
-            var trailing = buffer.trailingString;
-            if (!trailing.endsWith("url-prefix()") &&
-                !trailing.endsWith("url-prefix('')") &&
-                !trailing.endsWith('url-prefix("")')) {
-              needsDeprecationWarning = true;
-            }
-
-          case "regexp":
-            buffer.write("regexp(");
-            scanner.expectChar($lparen);
-            buffer.addInterpolation(interpolatedString().asInterpolation());
-            scanner.expectChar($rparen);
-            buffer.writeCharCode($rparen);
-            needsDeprecationWarning = true;
-
-          default:
-            error("Invalid function name.", scanner.spanFrom(identifierStart));
-        }
-      }
-
-      whitespace();
-      if (!scanner.scanChar($comma)) break;
-
-      buffer.writeCharCode($comma);
-      buffer.write(rawText(whitespace));
-    }
-
-    var value = buffer.interpolation(scanner.spanFrom(valueStart));
-    return _withChildren(_statement, start, (children, span) {
-      if (needsDeprecationWarning) {
-        warnings.add((
-          deprecation: Deprecation.mozDocument,
-          message:
-              "@-moz-document is deprecated and support will be removed in "
-              "Dart Sass 2.0.0.\n"
-              "\n"
-              "For details, see https://sass-lang.com/d/moz-document.",
-          span: span
-        ));
-      }
-
-      return AtRule(name, span, value: value, children: children);
-    });
-  }
-
   /// Consumes a `@return` rule.
   ///
   /// [start] should point before the `@`.
diff --git a/pkg/sass-parser/CHANGELOG.md b/pkg/sass-parser/CHANGELOG.md
index 8af6f962c..9ea24aee2 100644
--- a/pkg/sass-parser/CHANGELOG.md
+++ b/pkg/sass-parser/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.5.0
+
+* No user-visible changes.
+
 ## 0.4.3
 
 * Add support for parsing the `@while` rule.
diff --git a/pkg/sass-parser/package.json b/pkg/sass-parser/package.json
index 9b5fc6fa9..c30adb216 100644
--- a/pkg/sass-parser/package.json
+++ b/pkg/sass-parser/package.json
@@ -1,6 +1,6 @@
 {
   "name": "sass-parser",
-  "version": "0.4.3",
+  "version": "0.5.0-dev",
   "description": "A PostCSS-compatible wrapper of the official Sass parser",
   "repository": "sass/sass",
   "author": "Google Inc.",
diff --git a/pkg/sass_api/CHANGELOG.md b/pkg/sass_api/CHANGELOG.md
index 8d2a119ac..4f10ea3c1 100644
--- a/pkg/sass_api/CHANGELOG.md
+++ b/pkg/sass_api/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 15.0.0
+
+* No user-visible changes.
+
 ## 14.1.2
 
 * No user-visible changes.
diff --git a/pkg/sass_api/pubspec.yaml b/pkg/sass_api/pubspec.yaml
index 8bddb43bf..1fcb5d5ec 100644
--- a/pkg/sass_api/pubspec.yaml
+++ b/pkg/sass_api/pubspec.yaml
@@ -2,7 +2,7 @@ name: sass_api
 # Note: Every time we add a new Sass AST node, we need to bump the *major*
 # version because it's a breaking change for anyone who's implementing the
 # visitor interface(s).
-version: 14.1.2
+version: 15.0.0-dev
 description: Additional APIs for Dart Sass.
 homepage: https://github.com/sass/dart-sass
 
@@ -10,7 +10,7 @@ environment:
   sdk: ">=3.3.0 <4.0.0"
 
 dependencies:
-  sass: 1.80.6
+  sass: 2.0.0
 
 dev_dependencies:
   dartdoc: ^8.0.14
diff --git a/pubspec.yaml b/pubspec.yaml
index 6e148ca9f..924008fcd 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: sass
-version: 1.80.6
+version: 2.0.0-dev
 description: A Sass implementation in Dart.
 homepage: https://github.com/sass/dart-sass
 
diff --git a/test/deprecations_test.dart b/test/deprecations_test.dart
index 5841ea323..820a6b49b 100644
--- a/test/deprecations_test.dart
+++ b/test/deprecations_test.dart
@@ -20,12 +20,6 @@ void main() {
     _expectDeprecation("@if false {} @elseif false {}", Deprecation.elseif);
   });
 
-  // Deprecated in 1.7.2
-  test("mozDocument is violated by most @-moz-document rules", () {
-    _expectDeprecation(
-        "@-moz-document url-prefix(foo) {}", Deprecation.mozDocument);
-  });
-
   // Deprecated in 1.17.2
   test("newGlobal is violated by declaring a new variable with !global", () {
     _expectDeprecation(r"a {$foo: bar !global;}", Deprecation.newGlobal);