diff --git a/backend/src/feed.rs b/backend/src/feed.rs
index 099ab1e..c34a179 100644
--- a/backend/src/feed.rs
+++ b/backend/src/feed.rs
@@ -144,10 +144,10 @@ pub struct Pong<'a>(pub &'a str);
 pub struct AfgFinalized(pub Address, pub BlockNumber, pub BlockHash);
 
 #[derive(Serialize)]
-pub struct AfgReceivedPrevote(pub Address, pub BlockNumber, pub BlockHash, pub Address);
+pub struct AfgReceivedPrevote(pub Address, pub BlockNumber, pub BlockHash, pub Option<Address>);
 
 #[derive(Serialize)]
-pub struct AfgReceivedPrecommit(pub Address, pub BlockNumber, pub BlockHash, pub Address);
+pub struct AfgReceivedPrecommit(pub Address, pub BlockNumber, pub BlockHash, pub Option<Address>);
 
 #[derive(Serialize)]
 pub struct AfgAuthoritySet(pub Address, pub Address, pub Address, pub BlockNumber, pub BlockHash);
diff --git a/backend/src/node/message.rs b/backend/src/node/message.rs
index ae81226..25ae4cd 100644
--- a/backend/src/node/message.rs
+++ b/backend/src/node/message.rs
@@ -100,7 +100,7 @@ pub struct AfgFinalized {
 pub struct AfgReceived {
     pub target_hash: BlockHash,
     pub target_number: Box<str>,
-    pub voter: Box<str>,
+    pub voter: Option<Box<str>>,
 }
 
 #[derive(Deserialize, Debug, Clone)]