diff --git a/Cargo.lock b/Cargo.lock
index a4a84b95..2d2bb8fd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -735,9 +735,9 @@ dependencies = [
 
 [[package]]
 name = "hugr"
-version = "0.5.1"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a20246e5f1a0aae160b80b71bc4d5c1dcccc5605dbe6458ac6f9af73137339c3"
+checksum = "79e9896b1c2f2760f71e05e8e56492e98f828e4abb17055055f851752c54720a"
 dependencies = [
  "hugr-core",
  "hugr-passes",
@@ -745,9 +745,9 @@ dependencies = [
 
 [[package]]
 name = "hugr-cli"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f3d973149618f24c966ea90cfaf5955c184b670d38b18f3114a66a20dc5b712b"
+checksum = "cce7564fd98a98a3e6576b627f18294319e02664aa4765924defdc789062e5f6"
 dependencies = [
  "clap",
  "clap-stdin",
@@ -759,9 +759,9 @@ dependencies = [
 
 [[package]]
 name = "hugr-core"
-version = "0.2.0"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd64c708ba21cedae58e37f3557d139ee6eaeaaa7df0ab9541385249c1ee6065"
+checksum = "86da0c1e47982cb16d20911c33af448cae7b4aa36f1f5ff44753c38dbb152aae"
 dependencies = [
  "bitvec",
  "cgmath",
@@ -790,9 +790,9 @@ dependencies = [
 
 [[package]]
 name = "hugr-passes"
-version = "0.2.0"
+version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7522d3a5299a49ee453f6d0e3c3a6e8e7ed08a38cbd11e1d19163b97098ce9be"
+checksum = "f4ae0241e13fc66d944faaa7c25b4062336274e6d533a0da05b55fa9b8b601df"
 dependencies = [
  "hugr-core",
  "itertools 0.13.0",
diff --git a/Cargo.toml b/Cargo.toml
index ffde4770..e80ea55f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,9 +25,9 @@ missing_docs = "warn"
 [workspace.dependencies]
 
 tket2 = { path = "./tket2" }
-hugr = "0.5.1"
-hugr-cli = "0.1.1"
-hugr-core = "0.2.0"
+hugr = "0.6.1"
+hugr-cli = "0.1.2"
+hugr-core = "0.3.1"
 portgraph = "0.12"
 pyo3 = "0.21.2"
 itertools = "0.13.0"
diff --git a/tket2/src/circuit.rs b/tket2/src/circuit.rs
index cfe3da4f..6770870d 100644
--- a/tket2/src/circuit.rs
+++ b/tket2/src/circuit.rs
@@ -15,7 +15,6 @@ use hugr_core::hugr::internal::HugrMutInternals;
 use itertools::Either::{Left, Right};
 
 use hugr::hugr::hugrmut::HugrMut;
-use hugr::hugr::NodeType;
 use hugr::ops::dataflow::IOTrait;
 use hugr::ops::{Input, NamedOp, OpParent, OpTag, OpTrait, Output};
 use hugr::types::{FunctionType, PolyFuncType};
@@ -528,10 +527,7 @@ fn update_signature(
         types.remove(in_index);
         types.into()
     };
-    let new_inp_op = Input::new(inp_types.clone());
-    let inp_exts = hugr.get_nodetype(inp).input_extensions().cloned();
-    hugr.replace_op(inp, NodeType::new(new_inp_op, inp_exts))
-        .unwrap();
+    hugr.replace_op(inp, Input::new(inp_types.clone())).unwrap();
 
     // Update output node if necessary.
     let out_types = out_index.map(|out_index| {
@@ -544,17 +540,14 @@ fn update_signature(
             types.remove(out_index);
             types.into()
         };
-        let new_out_op = Output::new(out_types.clone());
-        let inp_exts = hugr.get_nodetype(out).input_extensions().cloned();
-        hugr.replace_op(out, NodeType::new(new_out_op, inp_exts))
+        hugr.replace_op(out, Output::new(out_types.clone()))
             .unwrap();
         out_types
     });
 
     // Update the parent's signature
-    let nodetype = hugr.get_nodetype(parent).clone();
-    let input_extensions = nodetype.input_extensions().cloned();
-    let mut optype = nodetype.into_op();
+    let mut optype = hugr.get_optype(parent).clone();
+
     // Replace the parent node operation with the right operation type
     // This must be able to process all implementers of `DataflowParent`.
     match &mut optype {
@@ -594,7 +587,7 @@ fn update_signature(
         })?,
     }
 
-    hugr.replace_op(parent, NodeType::new(optype, input_extensions))?;
+    hugr.replace_op(parent, optype)?;
 
     Ok(())
 }
diff --git a/tket2/src/circuit/command.rs b/tket2/src/circuit/command.rs
index d1cd8223..88de1e7e 100644
--- a/tket2/src/circuit/command.rs
+++ b/tket2/src/circuit/command.rs
@@ -7,7 +7,7 @@ use std::collections::{HashMap, HashSet};
 use std::iter::FusedIterator;
 
 use hugr::hugr::views::{HierarchyView, SiblingGraph};
-use hugr::hugr::{NodeMetadata, NodeType};
+use hugr::hugr::NodeMetadata;
 use hugr::ops::{OpTag, OpTrait};
 use hugr::{HugrView, IncomingPort, OutgoingPort};
 use itertools::Either::{self, Left, Right};
@@ -40,12 +40,6 @@ impl<'circ, T: HugrView> Command<'circ, T> {
         self.node
     }
 
-    /// Returns the [`NodeType`] of the command.
-    #[inline]
-    pub fn nodetype(&self) -> &NodeType {
-        self.circ.hugr().get_nodetype(self.node)
-    }
-
     /// Returns the [`OpType`] of the command.
     #[inline]
     pub fn optype(&self) -> &OpType {
diff --git a/tket2/src/circuit/extract_dfg.rs b/tket2/src/circuit/extract_dfg.rs
index 17c10ed2..c5b5bb72 100644
--- a/tket2/src/circuit/extract_dfg.rs
+++ b/tket2/src/circuit/extract_dfg.rs
@@ -1,7 +1,6 @@
 //! Internal implementation of `Circuit::extract_dfg`.
 
 use hugr::hugr::hugrmut::HugrMut;
-use hugr::hugr::NodeType;
 use hugr::ops::{OpTrait, OpType, Output, DFG};
 use hugr::types::{FunctionType, SumType, TypeEnum};
 use hugr::HugrView;
@@ -26,10 +25,7 @@ pub(super) fn rewrite_into_dfg(circ: &mut Circuit) -> Result<(), CircuitMutError
     };
 
     let dfg = DFG { signature };
-    let nodetype = circ.hugr.get_nodetype(circ.parent());
-    let input_extensions = nodetype.input_extensions().cloned();
-    let nodetype = NodeType::new(OpType::DFG(dfg), input_extensions);
-    circ.hugr.replace_op(circ.parent(), nodetype)?;
+    circ.hugr.replace_op(circ.parent(), OpType::DFG(dfg))?;
 
     Ok(())
 }
@@ -50,8 +46,7 @@ fn remove_cfg_empty_output_tuple(
     let input_node = circ.input_node();
 
     let output_node = circ.output_node();
-    let output_nodetype = circ.hugr.get_nodetype(output_node).clone();
-    let output_op = output_nodetype.op();
+    let output_op = circ.hugr.get_optype(output_node).clone();
 
     let output_sig = output_op
         .dataflow_signature()
@@ -89,16 +84,7 @@ fn remove_cfg_empty_output_tuple(
     let new_op = Output {
         types: new_types.clone().into(),
     };
-    let new_node = hugr.add_node_after(
-        input_node,
-        NodeType::new(
-            new_op,
-            output_nodetype
-                .input_extensions()
-                .cloned()
-                .unwrap_or_default(),
-        ),
-    );
+    let new_node = hugr.add_node_after(input_node, new_op);
 
     // Reconnect the outputs.
     for (i, (neigh, port)) in input_neighs.into_iter().enumerate() {
diff --git a/tket2/src/passes/chunks.rs b/tket2/src/passes/chunks.rs
index f1a40715..fba83be9 100644
--- a/tket2/src/passes/chunks.rs
+++ b/tket2/src/passes/chunks.rs
@@ -308,7 +308,7 @@ impl CircuitChunks {
             .and_then(|s| s.as_str())
             .unwrap_or("");
 
-        let mut builder = FunctionBuilder::new(name, self.signature.into()).unwrap();
+        let mut builder = FunctionBuilder::new(name, self.signature).unwrap();
         // Take the unfinished Hugr from the builder, to avoid unnecessary
         // validation checks that require connecting the inputs an outputs.
         let mut reassembled = mem::take(builder.hugr_mut());
diff --git a/tket2/src/passes/pytket.rs b/tket2/src/passes/pytket.rs
index 9def01fa..b9f1d1fb 100644
--- a/tket2/src/passes/pytket.rs
+++ b/tket2/src/passes/pytket.rs
@@ -70,13 +70,12 @@ mod test {
 
             let mut builder = ModuleBuilder::new();
             let _func = {
-                let mut func = builder.define_function("main", circ_signature.into())?;
+                let mut func = builder.define_function("main", circ_signature)?;
                 let [q1, q2] = func.input_wires_arr();
 
                 let cfg = {
                     let mut cfg = func.cfg_builder(
                         [(QB_T, q1), (QB_T, q2)],
-                        None,
                         two_qbs.clone(),
                         ExtensionSet::new(),
                     )?;
diff --git a/tket2/src/serialize/pytket/decoder.rs b/tket2/src/serialize/pytket/decoder.rs
index b1f2eeb5..8c70249b 100644
--- a/tket2/src/serialize/pytket/decoder.rs
+++ b/tket2/src/serialize/pytket/decoder.rs
@@ -48,7 +48,7 @@ impl Tk1Decoder {
             .with_extension_delta(TKET1_EXTENSION_ID);
 
         let name = serialcirc.name.clone().unwrap_or_default();
-        let mut dfg = FunctionBuilder::new(name, sig.into()).unwrap();
+        let mut dfg = FunctionBuilder::new(name, sig).unwrap();
         let dangling_wires = dfg.input_wires().collect::<Vec<_>>();
 
         // Metadata. The circuit requires "name", and we store other things that
diff --git a/tket2/src/utils.rs b/tket2/src/utils.rs
index e6578c47..55af83a9 100644
--- a/tket2/src/utils.rs
+++ b/tket2/src/utils.rs
@@ -28,7 +28,7 @@ where
     let qb_row = vec![QB_T; num_qubits];
     let signature =
         FunctionType::new(qb_row.clone(), qb_row).with_extension_delta(float_types::EXTENSION_ID);
-    let mut h = FunctionBuilder::new("main", signature.into())?;
+    let mut h = FunctionBuilder::new("main", signature)?;
 
     let qbs = h.input_wires();
 
@@ -53,7 +53,7 @@ where
     let circ = {
         let qb_row = vec![QB_T; num_qubits];
         let circ_signature = FunctionType::new(qb_row.clone(), qb_row);
-        let mut dfg = builder.define_function("main", circ_signature.into())?;
+        let mut dfg = builder.define_function("main", circ_signature)?;
         let mut circ = dfg.as_circuit(dfg.input_wires());
         f(&mut circ)?;
         let qbs = circ.finish();