diff --git a/proto/ModelConfig.proto b/proto/ModelConfig.proto
index 14c745b532092cbd4023343e0906acbbf19daf3e..1ea1e052596524f5baa0a55f601c4fa928acd8af 100644
--- a/proto/ModelConfig.proto
+++ b/proto/ModelConfig.proto
@@ -83,8 +83,8 @@ message ConvConfig {
   // if not set, use img_size
   optional uint32 img_size_y = 14;
 
-  required uint32 dilation = 15 [ default = 1 ];
-  required uint32 dilation_y = 16 [ default = 1 ];
+  optional uint32 dilation = 15 [ default = 1 ];
+  optional uint32 dilation_y = 16 [ default = 1 ];
 }
 
 message PoolConfig {