diff --git a/src/query.rs b/src/query.rs
index 5eb20d1..44f8973 100644
--- a/src/query.rs
+++ b/src/query.rs
@@ -18,14 +18,14 @@ pub struct Query<'a> {
 
 pub struct FundingOutput {
     pub txn_id: Sha256dHash,
-    pub height: u32,
+    pub height: i32,
     pub output_index: usize,
     pub value: u64,
 }
 
 pub struct SpendingInput {
     pub txn_id: Sha256dHash,
-    pub height: u32,
+    pub height: i32,
     pub input_index: usize,
 }
 
@@ -37,7 +37,7 @@ pub struct Status {
 
 struct TxnHeight {
     txn: Transaction,
-    height: u32,
+    height: i32,
 }
 
 fn merklize(left: Sha256dHash, right: Sha256dHash) -> Sha256dHash {
@@ -63,7 +63,10 @@ impl<'a> Query<'a> {
                 let txid: Sha256dHash = deserialize(&key.txid).unwrap();
                 let txn: Transaction = self.get_tx(&txid);
                 let height: u32 = bincode::deserialize(&row.value).unwrap();
-                txns.push(TxnHeight { txn, height })
+                txns.push(TxnHeight {
+                    txn,
+                    height: height as i32,
+                })
             }
         }
         txns
diff --git a/src/rpc.rs b/src/rpc.rs
index 8f8a9b6..b0ed416 100644
--- a/src/rpc.rs
+++ b/src/rpc.rs
@@ -25,15 +25,15 @@ fn hash_from_value(val: Option<&Value>) -> Result<Sha256dHash> {
     Ok(script_hash)
 }
 
-fn history_from_status(status: &Status) -> Vec<(u32, Sha256dHash)> {
-    let mut txns_map = HashMap::<Sha256dHash, u32>::new();
+fn history_from_status(status: &Status) -> Vec<(i32, Sha256dHash)> {
+    let mut txns_map = HashMap::<Sha256dHash, i32>::new();
     for f in &status.funding {
         txns_map.insert(f.txn_id, f.height);
     }
     for s in &status.spending {
         txns_map.insert(s.txn_id, s.height);
     }
-    let mut txns: Vec<(u32, Sha256dHash)> =
+    let mut txns: Vec<(i32, Sha256dHash)> =
         txns_map.into_iter().map(|item| (item.1, item.0)).collect();
     txns.sort();
     txns