diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc
index e2de4608816..68b489e4ea4 100755
Binary files a/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc and b/proto/compiler/google/src/google/protobuf/compiler/kotlin/protoc differ
diff --git a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc
index 91200759842..c1047401aa0 100644
--- a/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc
+++ b/proto/compiler/google/src/google/protobuf/compiler/kotlin/src/kotlin_field_generator.cc
@@ -107,7 +107,7 @@ void FieldGenerator::generateSerializationCode(io::Printer *printer, bool isRead
             // TODO: stub here, resolve name properly!
             vars["builderType"] = getUnderlyingTypeGenerator().getFullType();
             vars["initValue"] = getUnderlyingTypeGenerator().getInitValue();
-            printer->Print(vars, "val tmp: $builderType$ = $initValue$\n");
+            printer->Print(vars, "var tmp: $builderType$ = $initValue$\n");
             singleFieldGen.simpleName = "tmp";
             singleFieldGen.protoLabel = FieldDescriptor::LABEL_OPTIONAL;