diff --git a/heed/src/envs/env.rs b/heed/src/envs/env.rs
index 8180e617..51e6ffd1 100644
--- a/heed/src/envs/env.rs
+++ b/heed/src/envs/env.rs
@@ -537,6 +537,7 @@ impl Env<WithoutTls> {
     ///
     /// # Ok(()) }
     /// ```
+    #[cfg(not(master3))]
     pub fn nested_read_txn<'p>(&'p self, parent: &'p RwTxn) -> Result<RoTxn<'p, WithoutTls>> {
         RoTxn::<WithoutTls>::nested(self, parent)
     }
diff --git a/heed/src/txn.rs b/heed/src/txn.rs
index 304c7fab..7e23338e 100644
--- a/heed/src/txn.rs
+++ b/heed/src/txn.rs
@@ -84,6 +84,7 @@ impl<'e, T> RoTxn<'e, T> {
         Ok(RoTxn { txn: NonNull::new(txn), env: Cow::Owned(env), _tls_marker: PhantomData })
     }
 
+    #[cfg(not(master3))]
     pub(crate) fn nested<'p>(
         env: &'p Env<WithoutTls>,
         parent: &'p RwTxn,