diff --git a/lib/state/block.rs b/lib/state/block.rs
index 16241b2..1f0e999 100644
--- a/lib/state/block.rs
+++ b/lib/state/block.rs
@@ -566,7 +566,7 @@ pub fn disconnect_tip(
                     rwtxn,
                     &filled_tx,
                     (**bitname_updates).clone(),
-                    height - 1,
+                    height,
                 )?;
             }
             Some(TxData::BatchIcann(batch_icann_data)) => {
@@ -650,3 +650,164 @@ pub fn disconnect_tip(
     }
     Ok(())
 }
+
+#[cfg(test)]
+mod test {
+    use bitcoin::hashes::Hash as _;
+
+    use crate::{
+        authorization::{self, SigningKey},
+        state::{
+            block::{connect, disconnect_tip, validate},
+            test::fresh_state,
+        },
+        types::{
+            BitName, BitNameDataUpdates, BitNameSeqId, BlockHash, Body,
+            FilledOutput, FilledOutputContent, FilledTransaction, Hash, Header,
+            MerkleRoot, MutableBitNameData, OutPoint, OutPointKey, Output,
+            OutputContent, Transaction, TxData, Update,
+        },
+    };
+
+    fn header(
+        prev_side_hash: Option<BlockHash>,
+        merkle_root: MerkleRoot,
+    ) -> Header {
+        Header {
+            merkle_root,
+            prev_side_hash,
+            prev_main_hash: bitcoin::BlockHash::from_byte_array([0; 32]),
+        }
+    }
+
+    fn all_retained_updates() -> BitNameDataUpdates {
+        BitNameDataUpdates {
+            commitment: Update::Retain,
+            socket_addr_v4: Update::Retain,
+            socket_addr_v6: Update::Retain,
+            encryption_pubkey: Update::Retain,
+            signing_pubkey: Update::Retain,
+            paymail_fee_sats: Update::Retain,
+        }
+    }
+
+    #[test]
+    fn disconnect_bitname_data_update() -> anyhow::Result<()> {
+        let (env, state) = fresh_state("disconnect_bitname_data_update")?;
+        let signing_key = SigningKey::from_bytes(&[7; 32]);
+        let verifying_key = signing_key.verifying_key().into();
+        let address = authorization::get_address(&verifying_key);
+
+        let name_hash: Hash = [1; 32];
+        let revealed_nonce: Hash = [2; 32];
+        let commitment: Hash =
+            blake3::keyed_hash(&revealed_nonce, &name_hash).into();
+        let reservation_txid = [3; 32].into();
+        let bitname = BitName(name_hash);
+        let bitname_outpoint = OutPoint::Regular {
+            txid: [5; 32].into(),
+            vout: 0,
+        };
+
+        {
+            let mut rwtxn = env.write_txn()?;
+            state.bitnames.put_reservation(
+                &mut rwtxn,
+                &reservation_txid,
+                &commitment,
+            )?;
+            let registration_tx = Transaction {
+                inputs: vec![OutPoint::Regular {
+                    txid: reservation_txid,
+                    vout: 0,
+                }],
+                outputs: Vec::new(),
+                memo: Vec::new(),
+                data: Some(TxData::BitNameRegistration {
+                    name_hash: bitname,
+                    revealed_nonce,
+                    bitname_data: Box::new(MutableBitNameData::default()),
+                }),
+            };
+            let registration_filled = crate::types::FilledTransaction {
+                transaction: registration_tx,
+                spent_utxos: vec![FilledOutput {
+                    address,
+                    content: FilledOutputContent::BitNameReservation(
+                        reservation_txid,
+                        commitment,
+                    ),
+                    memo: Vec::new(),
+                }],
+            };
+            state.bitnames.apply_registration(
+                &mut rwtxn,
+                &registration_filled,
+                bitname,
+                &MutableBitNameData::default(),
+                0,
+            )?;
+            let seq = state.bitnames.next_seq(&rwtxn)?;
+            anyhow::ensure!(seq == BitNameSeqId::new(1));
+            state.utxos.put(
+                &mut rwtxn,
+                &OutPointKey::from_outpoint(&bitname_outpoint),
+                &FilledOutput {
+                    address,
+                    content: FilledOutputContent::BitName(bitname),
+                    memo: Vec::new(),
+                },
+            )?;
+            rwtxn.commit()?;
+        }
+
+        let genesis_body = Body {
+            coinbase: Vec::new(),
+            transactions: Vec::new(),
+            authorizations: Vec::new(),
+        };
+        let genesis_merkle_root =
+            Body::compute_merkle_root::<FilledTransaction>(&[], &[])?;
+        let genesis_header = header(None, genesis_merkle_root);
+        {
+            let mut rwtxn = env.write_txn()?;
+            connect(&state, &mut rwtxn, &genesis_header, &genesis_body)?;
+            rwtxn.commit()?;
+        }
+
+        let mut updates = all_retained_updates();
+        updates.commitment = Update::Set([9; 32]);
+        let update_tx = Transaction {
+            inputs: vec![bitname_outpoint],
+            outputs: vec![Output::new(address, OutputContent::BitName)],
+            memo: Vec::new(),
+            data: Some(TxData::BitNameUpdate(Box::new(updates))),
+        };
+        let filled_update_tx = {
+            let rotxn = env.read_txn()?;
+            state.fill_transaction(&rotxn, &update_tx)?
+        };
+        let authorized_update =
+            authorization::authorize(&[(address, &signing_key)], update_tx)?;
+        let update_body = Body::new(vec![authorized_update], Vec::new());
+        let update_merkle_root =
+            Body::compute_merkle_root(&[], &[filled_update_tx])?;
+        let update_header =
+            header(Some(genesis_header.hash()), update_merkle_root);
+
+        {
+            let rotxn = env.read_txn()?;
+            validate(&state, &rotxn, &update_header, &update_body)?;
+        }
+        {
+            let mut rwtxn = env.write_txn()?;
+            connect(&state, &mut rwtxn, &update_header, &update_body)?;
+            rwtxn.commit()?;
+        }
+
+        let mut rwtxn = env.write_txn()?;
+        let () =
+            disconnect_tip(&state, &mut rwtxn, &update_header, &update_body)?;
+        Ok(())
+    }
+}