diff --git a/tensorflow/compiler/tf2tensorrt/ops/trt_engine_op.cc b/tensorflow/compiler/tf2tensorrt/ops/trt_engine_op.cc
index b84d2fe0b8c..791ddc41b4f 100644
--- a/tensorflow/compiler/tf2tensorrt/ops/trt_engine_op.cc
+++ b/tensorflow/compiler/tf2tensorrt/ops/trt_engine_op.cc
@@ -24,12 +24,9 @@ limitations under the License.
 
 namespace tensorflow {
 
-namespace shape_inference {
-extern Status TRTEngineOpShapeInference(InferenceContext* c);
-}
-
-// NOTE: please try NOT to add/modify/remove attributes or inputs/outputs to the
-// list below, this will break backward compatibility!
+// NOTE: when making changes please follow
+// https://www.tensorflow.org/guide/extend/op#backwards_compatibility to not
+// break backward compatibility.
 //
 // TODO(laigd): consider making this op stateful. The only problem is it uses TF
 // function which has to be stateless, but we can use function library as the
@@ -41,8 +38,6 @@ REGISTER_OP("TRTEngineOp")
     .Attr("segment_funcdef_name: string")
     .Attr("InT: list({int8,float16,float32,int32})")
     .Attr("OutT: list({int8,float16,float32,int32})")
-    .Attr("static_engine: bool = true")
-    .Attr("fixed_input_size: bool = true")
     .Attr("cached_engine_batches: list(int) >= 0 = []")
     .Attr("max_cached_engines_count: int = 1")
     .Attr("workspace_size_bytes: int")
@@ -57,8 +52,10 @@ REGISTER_OP("TRTEngineOp")
     // implementation, we do require all input tensor to carry the same batch
     // size, but this could change in the future). Hence we disable shape
     // inference function as a workaround.
-    // .SetShapeFn(shape_inference::TRTEngineOpShapeInference);
-    .SetShapeFn(shape_inference::UnknownShape);
+    .SetShapeFn(shape_inference::UnknownShape)
+    // Deprecated attributes.
+    .Attr("fixed_input_size: bool = true")
+    .Attr("static_engine: bool = true");
 }  // namespace tensorflow
 
 #endif  // GOOGLE_TENSORRT