diff --git a/samples/client/petstore/dart2/flutter_petstore/openapi/pubspec.yaml b/samples/client/petstore/dart2/flutter_petstore/openapi/pubspec.yaml
index d54efb46a2e4..9ccf0e524ad0 100644
--- a/samples/client/petstore/dart2/flutter_petstore/openapi/pubspec.yaml
+++ b/samples/client/petstore/dart2/flutter_petstore/openapi/pubspec.yaml
@@ -1,5 +1,7 @@
 name: openapi
 version: 1.0.0
 description: OpenAPI API client
+environment:
+  sdk: '>=2.0.0 <3.0.0'
 dependencies:
   http: '>=0.11.1 <0.12.0'
diff --git a/samples/client/petstore/dart2/openapi-browser-client/pubspec.yaml b/samples/client/petstore/dart2/openapi-browser-client/pubspec.yaml
index d54efb46a2e4..9ccf0e524ad0 100644
--- a/samples/client/petstore/dart2/openapi-browser-client/pubspec.yaml
+++ b/samples/client/petstore/dart2/openapi-browser-client/pubspec.yaml
@@ -1,5 +1,7 @@
 name: openapi
 version: 1.0.0
 description: OpenAPI API client
+environment:
+  sdk: '>=2.0.0 <3.0.0'
 dependencies:
   http: '>=0.11.1 <0.12.0'
diff --git a/samples/client/petstore/dart2/openapi/pubspec.yaml b/samples/client/petstore/dart2/openapi/pubspec.yaml
index d54efb46a2e4..9ccf0e524ad0 100644
--- a/samples/client/petstore/dart2/openapi/pubspec.yaml
+++ b/samples/client/petstore/dart2/openapi/pubspec.yaml
@@ -1,5 +1,7 @@
 name: openapi
 version: 1.0.0
 description: OpenAPI API client
+environment:
+  sdk: '>=2.0.0 <3.0.0'
 dependencies:
   http: '>=0.11.1 <0.12.0'