diff --git a/.github/workflows/dart.yml b/.github/workflows/dart.yml
index 8e1e9bd..9593e13 100644
--- a/.github/workflows/dart.yml
+++ b/.github/workflows/dart.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        sdk: [stable, dev]
+        sdk: [3.0.0, dev]
     steps:
       - uses: actions/checkout@8e5e7e5ab8b370d6c329ec480221332ada57f0ab
       - uses: dart-lang/setup-dart@d6a63dab3335f427404425de0fbfed4686d93c4f
@@ -60,7 +60,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        sdk: [stable, dev]
+        sdk: [3.0.0, dev]
         platform: [vm, chrome]
         exclude:
           # We only run Chrome tests on Linux. No need to run them
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a05d0ca..ef0d1d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## 3.2.1
 
 * `package:http` now supports more versions: `>=0.13.0 <2.0.0`. 
+* `package:protobuf` new supports more versions: `>=2.0.0 <4.0.0`.
 
 ## 3.2.0
 
diff --git a/lib/src/client/common.dart b/lib/src/client/common.dart
index 5060fc1..5c63412 100644
--- a/lib/src/client/common.dart
+++ b/lib/src/client/common.dart
@@ -66,7 +66,8 @@ class ResponseFuture<R> extends DelegatingFuture<R>
 }
 
 /// A gRPC response producing a stream of values.
-class ResponseStream<R> extends StreamView<R> with _ResponseMixin<dynamic, R> {
+base class ResponseStream<R> extends StreamView<R>
+    with _ResponseMixin<dynamic, R> {
   @override
   final ClientCall<dynamic, R> _call;
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 86d6520..0fd0ae6 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -6,7 +6,7 @@ version: 3.2.1
 repository: https://github.com/grpc/grpc-dart
 
 environment:
-  sdk: '>=3.0.0 <4.0.0'
+  sdk: ^3.0.0
 
 dependencies:
   archive: ^3.0.0
@@ -17,7 +17,7 @@ dependencies:
   meta: ^1.3.0
   http: '>=0.13.0 <2.0.0'
   http2: ^2.0.0
-  protobuf: ^2.0.0
+  protobuf: '>=2.0.0 <4.0.0'
 
 dev_dependencies:
   build_runner: ^2.0.0