1 files changed, 2 insertions, 2 deletions
diff --git a/objectivec/GPBUnknownField.m b/objectivec/GPBUnknownField.m
index c49c0dfc..22ed66a4 100644
--- a/objectivec/GPBUnknownField.m
+++ b/objectivec/GPBUnknownField.m
@@ -39,8 +39,8 @@
   GPBUInt64Array *mutableVarintList_;
   GPBUInt32Array *mutableFixed32List_;
   GPBUInt64Array *mutableFixed64List_;
-  NSMutableArray *mutableLengthDelimitedList_;
-  NSMutableArray *mutableGroupList_;
+  NSMutableArray<NSData*> *mutableLengthDelimitedList_;
+  NSMutableArray<GPBUnknownFieldSet*> *mutableGroupList_;
 }
 
 @synthesize number = number_;