diff --git a/ic-utils/src/interfaces/http_request.rs b/ic-utils/src/interfaces/http_request.rs
index ee7f4eda..cdf04d84 100644
--- a/ic-utils/src/interfaces/http_request.rs
+++ b/ic-utils/src/interfaces/http_request.rs
@@ -75,6 +75,8 @@ pub struct StreamingCallbackHttpResponse<Token = self::Token> {
     pub body: Vec<u8>,
     /// The new stream continuation token.
     pub token: Option<Token>,
+    /// chunk witness tree.
+    pub chunk_tree: Option<Vec<u8>>,
 }
 
 /// A token for continuing a callback streaming strategy.
@@ -298,6 +300,7 @@ mod test {
                 index: 42.into(),
                 sha256: None,
             }),
+            chunk_tree: None,
         })
         .unwrap();
 
@@ -349,6 +352,7 @@ mod test {
         let bytes: Vec<u8> = Encode!(&StreamingCallbackHttpResponse {
             body: b"this is a body".as_ref().into(),
             token: Option::<pre_update_legacy::Token>::None,
+            chunk_tree: None,
         })
         .unwrap();