diff --git a/Cargo.lock b/Cargo.lock
index 427f1593f..2cf0ecbf3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -855,8 +855,7 @@ dependencies = [
 [[package]]
 name = "incrementalmerkletree"
 version = "0.3.0-beta.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cad6be282c89afc05aebe4801b0d5f9d6b7c556a8f398e447f4b26ea56a6b45e"
+source = "git+https://github.com/nuttycom/incrementalmerkletree?rev=027a98e53ad59699662d258ac22cd2095ae02aea#027a98e53ad59699662d258ac22cd2095ae02aea"
 dependencies = [
  "serde",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 5ed7955df..0e0b3bf60 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -87,6 +87,7 @@ codegen-units = 1
 
 [patch.crates-io]
 hdwallet = { git = "https://github.com/nuttycom/hdwallet", rev = "576683b9f2865f1118c309017ff36e01f84420c9" }
+incrementalmerkletree = { git = "https://github.com/nuttycom/incrementalmerkletree", rev = "027a98e53ad59699662d258ac22cd2095ae02aea" }
 zcash_address = { git = "https://github.com/zcash/librustzcash.git", rev = "9c1ed86c5aa8ae3b6d6dcc1478f2d6ba1264488f" }
 zcash_encoding = { git = "https://github.com/zcash/librustzcash.git", rev = "9c1ed86c5aa8ae3b6d6dcc1478f2d6ba1264488f" }
 zcash_history = { git = "https://github.com/zcash/librustzcash.git", rev = "9c1ed86c5aa8ae3b6d6dcc1478f2d6ba1264488f" }
diff --git a/src/rust/src/incremental_merkle_tree.rs b/src/rust/src/incremental_merkle_tree.rs
index ec2e31998..29d780122 100644
--- a/src/rust/src/incremental_merkle_tree.rs
+++ b/src/rust/src/incremental_merkle_tree.rs
@@ -5,7 +5,7 @@ use incrementalmerkletree::{
     bridgetree::{BridgeTree, Checkpoint},
     Hashable,
 };
-use zcash_encoding::Vector;
+use zcash_encoding::{Optional, Vector};
 use zcash_primitives::merkle_tree::{
     incremental::{
         read_bridge_v1, read_leu64_usize, read_position, write_bridge_v1, write_position,
@@ -14,18 +14,14 @@ use zcash_primitives::merkle_tree::{
     HashSer,
 };
 
-pub fn write_checkpoint_v1<H: HashSer + Ord, W: Write>(
-    mut writer: W,
-    checkpoint: &Checkpoint<H>,
-) -> io::Result<()> {
+pub fn write_checkpoint_v1<W: Write>(mut writer: W, checkpoint: &Checkpoint) -> io::Result<()> {
     write_usize_leu64(&mut writer, checkpoint.bridges_len())?;
     writer.write_u8(if checkpoint.is_witnessed() { 1 } else { 0 })?;
     Vector::write_sized(
         &mut writer,
         checkpoint.forgotten().iter(),
-        |mut w, ((pos, leaf_value), idx)| {
+        |mut w, (pos, idx)| {
             write_position(&mut w, *pos)?;
-            leaf_value.write(&mut w)?;
             write_usize_leu64(&mut w, *idx)
         },
     )?;
@@ -33,15 +29,12 @@ pub fn write_checkpoint_v1<H: HashSer + Ord, W: Write>(
     Ok(())
 }
 
-pub fn read_checkpoint_v1<H: HashSer + Ord, R: Read>(mut reader: R) -> io::Result<Checkpoint<H>> {
+pub fn read_checkpoint_v1<R: Read>(mut reader: R) -> io::Result<Checkpoint> {
     Ok(Checkpoint::from_parts(
         read_leu64_usize(&mut reader)?,
         reader.read_u8()? == 1,
         Vector::read_collected(&mut reader, |mut r| {
-            Ok((
-                (read_position(&mut r)?, H::read(&mut r)?),
-                read_leu64_usize(&mut r)?,
-            ))
+            Ok((read_position(&mut r)?, read_leu64_usize(&mut r)?))
         })?,
     ))
 }
@@ -50,13 +43,17 @@ pub fn write_tree_v1<H: Hashable + HashSer + Ord, W: Write>(
     mut writer: W,
     tree: &BridgeTree<H, 32>,
 ) -> io::Result<()> {
-    Vector::write(&mut writer, tree.bridges(), |w, b| write_bridge_v1(w, b))?;
+    Vector::write(&mut writer, tree.prior_bridges(), |w, b| {
+        write_bridge_v1(w, b)
+    })?;
+    Optional::write(&mut writer, tree.current_bridge().as_ref(), |w, b| {
+        write_bridge_v1(w, b)
+    })?;
     Vector::write_sized(
         &mut writer,
         tree.witnessed_indices().iter(),
-        |mut w, ((pos, a), i)| {
+        |mut w, (pos, i)| {
             write_position(&mut w, *pos)?;
-            a.write(&mut w)?;
             write_usize_leu64(&mut w, *i)
         },
     )?;
@@ -74,11 +71,9 @@ pub fn read_tree_v1<H: Hashable + HashSer + Ord + Clone, R: Read>(
 ) -> io::Result<BridgeTree<H, 32>> {
     BridgeTree::from_parts(
         Vector::read(&mut reader, |r| read_bridge_v1(r))?,
+        Optional::read(&mut reader, |r| read_bridge_v1(r))?,
         Vector::read_collected(&mut reader, |mut r| {
-            Ok((
-                (read_position(&mut r)?, H::read(&mut r)?),
-                read_leu64_usize(&mut r)?,
-            ))
+            Ok((read_position(&mut r)?, read_leu64_usize(&mut r)?))
         })?,
         Vector::read(&mut reader, |r| read_checkpoint_v1(r))?,
         read_leu64_usize(&mut reader)?,
diff --git a/src/rust/src/wallet.rs b/src/rust/src/wallet.rs
index 33960fbd7..765390e53 100644
--- a/src/rust/src/wallet.rs
+++ b/src/rust/src/wallet.rs
@@ -559,8 +559,7 @@ impl Wallet {
                 .and_then(|n| n.decrypted_notes.get(&action_idx))
                 .is_some()
             {
-                let (pos, cmx) = self.witness_tree.witness().expect("tree is not empty");
-                assert_eq!(cmx, MerkleHashOrchard::from_cmx(action.cmx()));
+                let pos = self.witness_tree.witness().expect("tree is not empty");
                 self.wallet_note_positions
                     .get_mut(txid)
                     .expect("We created this above")
@@ -653,12 +652,15 @@ impl Wallet {
                             .and_then(|tx_notes| tx_notes.note_positions.get(&outpoint.action_idx)),
                     )
                     .map(|(fvk, position)| {
+                        assert_eq!(
+                            self.witness_tree
+                                .get_witnessed_leaf(*position)
+                                .expect("tree has witnessed the leaf for this note."),
+                            &MerkleHashOrchard::from_cmx(&dnote.note.commitment().into()),
+                        );
                         let path = self
                             .witness_tree
-                            .authentication_path(
-                                *position,
-                                &MerkleHashOrchard::from_cmx(&dnote.note.commitment().into()),
-                            )
+                            .authentication_path(*position)
                             .expect("wallet always has paths to positioned notes");
                         OrchardSpendInfo::from_parts(
                             fvk.clone(),