diff --git a/src/event.h b/src/event.h
index a1aae44..a9bc24a 100644
--- a/src/event.h
+++ b/src/event.h
@@ -14,7 +14,6 @@ struct hyper_event_ops {
 	int		rbuf_size;
 	int		wbuf_size;
 	int		len_offset;
-	int		ack;
 };
 
 struct hyper_buf {
diff --git a/src/init.c b/src/init.c
index 7adfa40..3d46a91 100644
--- a/src/init.c
+++ b/src/init.c
@@ -1237,8 +1237,6 @@ static struct hyper_event_ops hyper_channel_ops = {
 	.handle		= hyper_channel_handle,
 	.rbuf_size	= 10240,
 	.len_offset	= 4,
-	/* TODO: vbox hyper should support channel ack */
-	.ack		= 1,
 };
 
 static struct hyper_event_ops hyper_ttyfd_ops = {