diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index 904d9941349..71fc1cb6f06 100644
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -262,7 +262,7 @@ impl_writeable_tlv_based!(HolderSignedTx, {
 	(8, delayed_payment_key, required),
 	(10, per_commitment_point, required),
 	(12, feerate_per_kw, required),
-	(14, htlc_outputs, vec_type)
+	(14, htlc_outputs, required_vec)
 });
 
 impl HolderSignedTx {
@@ -538,15 +538,15 @@ impl ChannelMonitorUpdateStep {
 impl_writeable_tlv_based_enum_upgradable!(ChannelMonitorUpdateStep,
 	(0, LatestHolderCommitmentTXInfo) => {
 		(0, commitment_tx, required),
-		(1, claimed_htlcs, vec_type),
-		(2, htlc_outputs, vec_type),
+		(1, claimed_htlcs, optional_vec),
+		(2, htlc_outputs, required_vec),
 		(4, nondust_htlc_sources, optional_vec),
 	},
 	(1, LatestCounterpartyCommitmentTXInfo) => {
 		(0, commitment_txid, required),
 		(2, commitment_number, required),
 		(4, their_per_commitment_point, required),
-		(6, htlc_outputs, vec_type),
+		(6, htlc_outputs, required_vec),
 	},
 	(2, PaymentPreimage) => {
 		(0, payment_preimage, required),
@@ -1075,12 +1075,12 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signe
 
 		write_tlv_fields!(writer, {
 			(1, self.funding_spend_confirmed, option),
-			(3, self.htlcs_resolved_on_chain, vec_type),
-			(5, self.pending_monitor_events, vec_type),
+			(3, self.htlcs_resolved_on_chain, required_vec),
+			(5, self.pending_monitor_events, required_vec),
 			(7, self.funding_spend_seen, required),
 			(9, self.counterparty_node_id, option),
 			(11, self.confirmed_commitment_tx_counterparty_output, option),
-			(13, self.spendable_txids_confirmed, vec_type),
+			(13, self.spendable_txids_confirmed, required_vec),
 			(15, self.counterparty_fulfilled_htlcs, required),
 		});
 
@@ -4051,12 +4051,12 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
 		let mut counterparty_fulfilled_htlcs = Some(HashMap::new());
 		read_tlv_fields!(reader, {
 			(1, funding_spend_confirmed, option),
-			(3, htlcs_resolved_on_chain, vec_type),
-			(5, pending_monitor_events, vec_type),
+			(3, htlcs_resolved_on_chain, optional_vec),
+			(5, pending_monitor_events, optional_vec),
 			(7, funding_spend_seen, option),
 			(9, counterparty_node_id, option),
 			(11, confirmed_commitment_tx_counterparty_output, option),
-			(13, spendable_txids_confirmed, vec_type),
+			(13, spendable_txids_confirmed, optional_vec),
 			(15, counterparty_fulfilled_htlcs, option),
 		});
 
diff --git a/lightning/src/events/mod.rs b/lightning/src/events/mod.rs
index a6601e4d99c..a5a20e7d42b 100644
--- a/lightning/src/events/mod.rs
+++ b/lightning/src/events/mod.rs
@@ -909,7 +909,7 @@ impl Writeable for Event {
 					(2, payment_failed_permanently, required),
 					(3, false, required), // all_paths_failed in LDK versions prior to 0.0.114
 					(4, path.blinded_tail, option),
-					(5, path.hops, vec_type),
+					(5, path.hops, required_vec),
 					(7, short_channel_id, option),
 					(9, None::<RouteParameters>, option), // retry in LDK versions prior to 0.0.115
 					(11, payment_id, option),
@@ -977,7 +977,7 @@ impl Writeable for Event {
 				write_tlv_fields!(writer, {
 					(0, payment_id, required),
 					(2, payment_hash, option),
-					(4, path.hops, vec_type),
+					(4, path.hops, required_vec),
 					(6, path.blinded_tail, option),
 				})
 			},
@@ -1008,7 +1008,7 @@ impl Writeable for Event {
 				write_tlv_fields!(writer, {
 					(0, payment_id, required),
 					(2, payment_hash, required),
-					(4, path.hops, vec_type),
+					(4, path.hops, required_vec),
 					(6, path.blinded_tail, option),
 				})
 			},
@@ -1017,7 +1017,7 @@ impl Writeable for Event {
 				write_tlv_fields!(writer, {
 					(0, payment_id, required),
 					(2, payment_hash, required),
-					(4, path.hops, vec_type),
+					(4, path.hops, required_vec),
 					(6, short_channel_id, option),
 					(8, path.blinded_tail, option),
 				})
@@ -1162,7 +1162,9 @@ impl MaybeReadable for Event {
 						(1, network_update, upgradable_option),
 						(2, payment_failed_permanently, required),
 						(4, blinded_tail, option),
-						(5, path, vec_type),
+						// Added as a part of LDK 0.0.101 and always filled in since.
+						// Defaults to an empty Vec, though likely should have been `Option`al.
+						(5, path, optional_vec),
 						(7, short_channel_id, option),
 						(11, payment_id, option),
 						(13, failure_opt, upgradable_option),
@@ -1279,13 +1281,13 @@ impl MaybeReadable for Event {
 					_init_and_read_tlv_fields!(reader, {
 						(0, payment_id, required),
 						(2, payment_hash, option),
-						(4, path, vec_type),
+						(4, path, required_vec),
 						(6, blinded_tail, option),
 					});
 					Ok(Some(Event::PaymentPathSuccessful {
 						payment_id: payment_id.0.unwrap(),
 						payment_hash,
-						path: Path { hops: path.unwrap(), blinded_tail },
+						path: Path { hops: path, blinded_tail },
 					}))
 				};
 				f()
@@ -1338,13 +1340,13 @@ impl MaybeReadable for Event {
 					_init_and_read_tlv_fields!(reader, {
 						(0, payment_id, required),
 						(2, payment_hash, required),
-						(4, path, vec_type),
+						(4, path, required_vec),
 						(6, blinded_tail, option),
 					});
 					Ok(Some(Event::ProbeSuccessful {
 						payment_id: payment_id.0.unwrap(),
 						payment_hash: payment_hash.0.unwrap(),
-						path: Path { hops: path.unwrap(), blinded_tail },
+						path: Path { hops: path, blinded_tail },
 					}))
 				};
 				f()
@@ -1354,14 +1356,14 @@ impl MaybeReadable for Event {
 					_init_and_read_tlv_fields!(reader, {
 						(0, payment_id, required),
 						(2, payment_hash, required),
-						(4, path, vec_type),
+						(4, path, required_vec),
 						(6, short_channel_id, option),
 						(8, blinded_tail, option),
 					});
 					Ok(Some(Event::ProbeFailed {
 						payment_id: payment_id.0.unwrap(),
 						payment_hash: payment_hash.0.unwrap(),
-						path: Path { hops: path.unwrap(), blinded_tail },
+						path: Path { hops: path, blinded_tail },
 						short_channel_id,
 					}))
 				};
diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs
index fd27d230866..85490afaec1 100644
--- a/lightning/src/ln/chan_utils.rs
+++ b/lightning/src/ln/chan_utils.rs
@@ -1056,7 +1056,7 @@ impl_writeable_tlv_based!(HolderCommitmentTransaction, {
 	(0, inner, required),
 	(2, counterparty_sig, required),
 	(4, holder_sig_first, required),
-	(6, counterparty_htlc_sigs, vec_type),
+	(6, counterparty_htlc_sigs, required_vec),
 });
 
 impl HolderCommitmentTransaction {
@@ -1346,7 +1346,7 @@ impl Writeable for CommitmentTransaction {
 			(6, self.feerate_per_kw, required),
 			(8, self.keys, required),
 			(10, self.built, required),
-			(12, self.htlcs, vec_type),
+			(12, self.htlcs, required_vec),
 			(14, legacy_deserialization_prevention_marker, option),
 			(15, self.channel_type_features, required),
 		});
@@ -1356,24 +1356,14 @@ impl Writeable for CommitmentTransaction {
 
 impl Readable for CommitmentTransaction {
 	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
-		let mut commitment_number = RequiredWrapper(None);
-		let mut to_broadcaster_value_sat = RequiredWrapper(None);
-		let mut to_countersignatory_value_sat = RequiredWrapper(None);
-		let mut feerate_per_kw = RequiredWrapper(None);
-		let mut keys = RequiredWrapper(None);
-		let mut built = RequiredWrapper(None);
-		_init_tlv_field_var!(htlcs, vec_type);
-		let mut _legacy_deserialization_prevention_marker: Option<()> = None;
-		let mut channel_type_features = None;
-
-		read_tlv_fields!(reader, {
+		_init_and_read_tlv_fields!(reader, {
 			(0, commitment_number, required),
 			(2, to_broadcaster_value_sat, required),
 			(4, to_countersignatory_value_sat, required),
 			(6, feerate_per_kw, required),
 			(8, keys, required),
 			(10, built, required),
-			(12, htlcs, vec_type),
+			(12, htlcs, required_vec),
 			(14, _legacy_deserialization_prevention_marker, option),
 			(15, channel_type_features, option),
 		});
@@ -1389,7 +1379,7 @@ impl Readable for CommitmentTransaction {
 			feerate_per_kw: feerate_per_kw.0.unwrap(),
 			keys: keys.0.unwrap(),
 			built: built.0.unwrap(),
-			htlcs: _init_tlv_based_struct_field!(htlcs, vec_type),
+			htlcs,
 			channel_type_features: channel_type_features.unwrap_or(ChannelTypeFeatures::only_static_remote_key())
 		})
 	}
diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 30280f0b1f1..95409fa1e5c 100644
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -6781,11 +6781,11 @@ impl<Signer: WriteableEcdsaChannelSigner> Writeable for Channel<Signer> {
 			(5, self.context.config, required),
 			(6, serialized_holder_htlc_max_in_flight, option),
 			(7, self.context.shutdown_scriptpubkey, option),
-			(8, self.context.blocked_monitor_updates, vec_type),
+			(8, self.context.blocked_monitor_updates, optional_vec),
 			(9, self.context.target_closing_feerate_sats_per_kw, option),
-			(11, self.context.monitor_pending_finalized_fulfills, vec_type),
+			(11, self.context.monitor_pending_finalized_fulfills, required_vec),
 			(13, self.context.channel_creation_height, required),
-			(15, preimages, vec_type),
+			(15, preimages, required_vec),
 			(17, self.context.announcement_sigs_state, required),
 			(19, self.context.latest_inbound_scid_alias, option),
 			(21, self.context.outbound_scid_alias, required),
@@ -7089,11 +7089,11 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
 			(5, config, option), // Note that if none is provided we will *not* overwrite the existing one.
 			(6, holder_max_htlc_value_in_flight_msat, option),
 			(7, shutdown_scriptpubkey, option),
-			(8, blocked_monitor_updates, vec_type),
+			(8, blocked_monitor_updates, optional_vec),
 			(9, target_closing_feerate_sats_per_kw, option),
-			(11, monitor_pending_finalized_fulfills, vec_type),
+			(11, monitor_pending_finalized_fulfills, optional_vec),
 			(13, channel_creation_height, option),
-			(15, preimages_opt, vec_type),
+			(15, preimages_opt, optional_vec),
 			(17, announcement_sigs_state, option),
 			(19, latest_inbound_scid_alias, option),
 			(21, outbound_scid_alias, option),
diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 980616770c8..b4b1d64acb1 100644
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -45,7 +45,7 @@ use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, No
 #[cfg(any(feature = "_test_utils", test))]
 use crate::ln::features::InvoiceFeatures;
 use crate::routing::gossip::NetworkGraph;
-use crate::routing::router::{BlindedTail, DefaultRouter, InFlightHtlcs, Path, Payee, PaymentParameters, Route, RouteHop, RouteParameters, Router};
+use crate::routing::router::{BlindedTail, DefaultRouter, InFlightHtlcs, Path, Payee, PaymentParameters, Route, RouteParameters, Router};
 use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 use crate::ln::msgs;
 use crate::ln::onion_utils;
@@ -3170,6 +3170,7 @@ where
 	/// irrevocably committed to on our end. In such a case, do NOT retry the payment with a
 	/// different route unless you intend to pay twice!
 	///
+	/// [`RouteHop`]: crate::routing::router::RouteHop
 	/// [`Event::PaymentSent`]: events::Event::PaymentSent
 	/// [`Event::PaymentFailed`]: events::Event::PaymentFailed
 	/// [`UpdateHTLCs`]: events::MessageSendEvent::UpdateHTLCs
@@ -7442,7 +7443,7 @@ impl Readable for ChannelDetails {
 }
 
 impl_writeable_tlv_based!(PhantomRouteHints, {
-	(2, channels, vec_type),
+	(2, channels, required_vec),
 	(4, phantom_scid, required),
 	(6, real_node_pubkey, required),
 });
@@ -7634,7 +7635,7 @@ impl Readable for HTLCSource {
 			0 => {
 				let mut session_priv: crate::util::ser::RequiredWrapper<SecretKey> = crate::util::ser::RequiredWrapper(None);
 				let mut first_hop_htlc_msat: u64 = 0;
-				let mut path_hops: Option<Vec<RouteHop>> = Some(Vec::new());
+				let mut path_hops = Vec::new();
 				let mut payment_id = None;
 				let mut payment_params: Option<PaymentParameters> = None;
 				let mut blinded_tail: Option<BlindedTail> = None;
@@ -7642,7 +7643,7 @@ impl Readable for HTLCSource {
 					(0, session_priv, required),
 					(1, payment_id, option),
 					(2, first_hop_htlc_msat, required),
-					(4, path_hops, vec_type),
+					(4, path_hops, required_vec),
 					(5, payment_params, (option: ReadableArgs, 0)),
 					(6, blinded_tail, option),
 				});
@@ -7651,7 +7652,7 @@ impl Readable for HTLCSource {
 					// instead.
 					payment_id = Some(PaymentId(*session_priv.0.unwrap().as_ref()));
 				}
-				let path = Path { hops: path_hops.ok_or(DecodeError::InvalidValue)?, blinded_tail };
+				let path = Path { hops: path_hops, blinded_tail };
 				if path.hops.len() == 0 {
 					return Err(DecodeError::InvalidValue);
 				}
@@ -7686,7 +7687,7 @@ impl Writeable for HTLCSource {
 					(1, payment_id_opt, option),
 					(2, first_hop_htlc_msat, required),
 					// 3 was previously used to write a PaymentSecret for the payment.
-					(4, path.hops, vec_type),
+					(4, path.hops, required_vec),
 					(5, None::<PaymentParameters>, option), // payment_params in LDK versions prior to 0.0.115
 					(6, path.blinded_tail, option),
 				 });
@@ -7936,7 +7937,7 @@ where
 			(6, monitor_update_blocked_actions_per_peer, option),
 			(7, self.fake_scid_rand_bytes, required),
 			(8, if events_not_backwards_compatible { Some(&*events) } else { None }, option),
-			(9, htlc_purposes, vec_type),
+			(9, htlc_purposes, required_vec),
 			(10, in_flight_monitor_updates, option),
 			(11, self.probing_cookie_secret, required),
 			(13, htlc_onion_fields, optional_vec),
@@ -8375,7 +8376,7 @@ where
 			(6, monitor_update_blocked_actions_per_peer, option),
 			(7, fake_scid_rand_bytes, option),
 			(8, events_override, option),
-			(9, claimable_htlc_purposes, vec_type),
+			(9, claimable_htlc_purposes, optional_vec),
 			(10, in_flight_monitor_updates, option),
 			(11, probing_cookie_secret, option),
 			(13, claimable_htlc_onion_fields, optional_vec),
diff --git a/lightning/src/ln/msgs.rs b/lightning/src/ln/msgs.rs
index 672c6ae6e96..a514f492326 100644
--- a/lightning/src/ln/msgs.rs
+++ b/lightning/src/ln/msgs.rs
@@ -3760,7 +3760,7 @@ mod tests {
 		let test_bytes = vec![42u8; 1000];
 		if let OnionHopDataFormat::NonFinalNode { short_channel_id } = payload.format {
 			_encode_varint_length_prefixed_tlv!(&mut encoded_payload, {
-				(1, test_bytes, vec_type),
+				(1, test_bytes, required_vec),
 				(2, HighZeroBytesDroppedBigSize(payload.amt_to_forward), required),
 				(4, HighZeroBytesDroppedBigSize(payload.outgoing_cltv_value), required),
 				(6, short_channel_id, required)
diff --git a/lightning/src/ln/onion_utils.rs b/lightning/src/ln/onion_utils.rs
index 3b62c856334..52eb7bcb542 100644
--- a/lightning/src/ln/onion_utils.rs
+++ b/lightning/src/ln/onion_utils.rs
@@ -645,7 +645,7 @@ impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
 	},
 	(1, Reason) => {
 		(0, failure_code, required),
-		(2, data, vec_type),
+		(2, data, required_vec),
 	},
 ;);
 
diff --git a/lightning/src/onion_message/packet.rs b/lightning/src/onion_message/packet.rs
index 1c3595c3712..8a5628f164c 100644
--- a/lightning/src/onion_message/packet.rs
+++ b/lightning/src/onion_message/packet.rs
@@ -169,7 +169,7 @@ impl<T: CustomOnionMessageContents> Writeable for (Payload<T>, [u8; 32]) {
 		match &self.0 {
 			Payload::Forward(ForwardControlTlvs::Blinded(encrypted_bytes)) => {
 				_encode_varint_length_prefixed_tlv!(w, {
-					(4, *encrypted_bytes, vec_type)
+					(4, *encrypted_bytes, required_vec)
 				})
 			},
 			Payload::Receive {
@@ -177,7 +177,7 @@ impl<T: CustomOnionMessageContents> Writeable for (Payload<T>, [u8; 32]) {
 			} => {
 				_encode_varint_length_prefixed_tlv!(w, {
 					(2, reply_path, option),
-					(4, *encrypted_bytes, vec_type),
+					(4, *encrypted_bytes, required_vec),
 					(message.tlv_type(), message, required)
 				})
 			},
diff --git a/lightning/src/routing/gossip.rs b/lightning/src/routing/gossip.rs
index 40969b180af..644772b8149 100644
--- a/lightning/src/routing/gossip.rs
+++ b/lightning/src/routing/gossip.rs
@@ -1120,26 +1120,26 @@ impl Writeable for NodeAnnouncementInfo {
 			(4, self.rgb, required),
 			(6, self.alias, required),
 			(8, self.announcement_message, option),
-			(10, empty_addresses, vec_type), // Versions prior to 0.0.115 require this field
+			(10, empty_addresses, required_vec), // Versions prior to 0.0.115 require this field
 		});
 		Ok(())
 	}
 }
 
 impl Readable for NodeAnnouncementInfo {
-    fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 		_init_and_read_tlv_fields!(reader, {
 			(0, features, required),
 			(2, last_update, required),
 			(4, rgb, required),
 			(6, alias, required),
 			(8, announcement_message, option),
-			(10, _addresses, vec_type), // deprecated, not used anymore
+			(10, _addresses, optional_vec), // deprecated, not used anymore
 		});
 		let _: Option<Vec<NetAddress>> = _addresses;
 		Ok(Self { features: features.0.unwrap(), last_update: last_update.0.unwrap(), rgb: rgb.0.unwrap(),
 			alias: alias.0.unwrap(), announcement_message })
-    }
+	}
 }
 
 /// A user-defined name for a node, which may be used when displaying the node in a graph.
@@ -1205,7 +1205,7 @@ impl Writeable for NodeInfo {
 		write_tlv_fields!(writer, {
 			// Note that older versions of LDK wrote the lowest inbound fees here at type 0
 			(2, self.announcement_info, option),
-			(4, self.channels, vec_type),
+			(4, self.channels, required_vec),
 		});
 		Ok(())
 	}
@@ -1236,19 +1236,17 @@ impl Readable for NodeInfo {
 		// with zero inbound fees, causing that heuristic to provide little gain. Worse, because it
 		// requires additional complexity and lookups during routing, it ends up being a
 		// performance loss. Thus, we simply ignore the old field here and no longer track it.
-		let mut _lowest_inbound_channel_fees: Option<RoutingFees> = None;
-		let mut announcement_info_wrap: Option<NodeAnnouncementInfoDeserWrapper> = None;
-		_init_tlv_field_var!(channels, vec_type);
-
-		read_tlv_fields!(reader, {
+		_init_and_read_tlv_fields!(reader, {
 			(0, _lowest_inbound_channel_fees, option),
 			(2, announcement_info_wrap, upgradable_option),
-			(4, channels, vec_type),
+			(4, channels, required_vec),
 		});
+		let _: Option<RoutingFees> = _lowest_inbound_channel_fees;
+		let announcement_info_wrap: Option<NodeAnnouncementInfoDeserWrapper> = announcement_info_wrap;
 
 		Ok(NodeInfo {
 			announcement_info: announcement_info_wrap.map(|w| w.0),
-			channels: _init_tlv_based_struct_field!(channels, vec_type),
+			channels,
 		})
 	}
 }
diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index ed5b772edad..8c00df99a7e 100644
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -283,7 +283,7 @@ pub struct BlindedTail {
 }
 
 impl_writeable_tlv_based!(BlindedTail, {
-	(0, hops, vec_type),
+	(0, hops, required_vec),
 	(2, blinding_point, required),
 	(4, excess_final_cltv_expiry_delta, required),
 	(6, final_value_msat, required),
@@ -550,10 +550,10 @@ impl Writeable for PaymentParameters {
 			(1, self.max_total_cltv_expiry_delta, required),
 			(2, self.payee.features(), option),
 			(3, self.max_path_count, required),
-			(4, *clear_hints, vec_type),
+			(4, *clear_hints, required_vec),
 			(5, self.max_channel_saturation_power_of_half, required),
 			(6, self.expiry_time, option),
-			(7, self.previously_failed_channels, vec_type),
+			(7, self.previously_failed_channels, required_vec),
 			(8, *blinded_hints, optional_vec),
 			(9, self.payee.final_cltv_expiry_delta(), option),
 		});
@@ -568,14 +568,13 @@ impl ReadableArgs<u32> for PaymentParameters {
 			(1, max_total_cltv_expiry_delta, (default_value, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA)),
 			(2, features, (option: ReadableArgs, payee_pubkey.is_some())),
 			(3, max_path_count, (default_value, DEFAULT_MAX_PATH_COUNT)),
-			(4, route_hints, vec_type),
+			(4, clear_route_hints, required_vec),
 			(5, max_channel_saturation_power_of_half, (default_value, DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF)),
 			(6, expiry_time, option),
-			(7, previously_failed_channels, vec_type),
+			(7, previously_failed_channels, optional_vec),
 			(8, blinded_route_hints, optional_vec),
 			(9, final_cltv_expiry_delta, (default_value, default_final_cltv_expiry_delta)),
 		});
-		let clear_route_hints = route_hints.unwrap_or(vec![]);
 		let blinded_route_hints = blinded_route_hints.unwrap_or(vec![]);
 		let payee = if blinded_route_hints.len() != 0 {
 			if clear_route_hints.len() != 0 || payee_pubkey.is_some() { return Err(DecodeError::InvalidValue) }
diff --git a/lightning/src/util/chacha20poly1305rfc.rs b/lightning/src/util/chacha20poly1305rfc.rs
index 052968377a5..a5bec2c82b8 100644
--- a/lightning/src/util/chacha20poly1305rfc.rs
+++ b/lightning/src/util/chacha20poly1305rfc.rs
@@ -341,9 +341,9 @@ mod tests {
 		field3: Vec<u8>,
 	}
 	impl_writeable_tlv_based!(TestWriteable, {
-		(1, field1, vec_type),
-		(2, field2, vec_type),
-		(3, field3, vec_type),
+		(1, field1, required_vec),
+		(2, field2, required_vec),
+		(3, field3, required_vec),
 	});
 
 	#[test]
diff --git a/lightning/src/util/ser_macros.rs b/lightning/src/util/ser_macros.rs
index 8ffcec6d175..710085e2bbd 100644
--- a/lightning/src/util/ser_macros.rs
+++ b/lightning/src/util/ser_macros.rs
@@ -13,6 +13,21 @@
 //! [`Readable`]: crate::util::ser::Readable
 //! [`Writeable`]: crate::util::ser::Writeable
 
+// There are quite a few TLV serialization "types" which behave differently. We currently only
+// publicly document the `optional` and `required` types, not supporting anything else publicly and
+// changing them at will.
+//
+// Some of the other types include:
+//  * (default_value, $default) - reads optionally, reading $default if no TLV is present
+//  * (static_value, $value) - ignores any TLVs, always using $value
+//  * required_vec - reads into a Vec without a length prefix, failing if no TLV is present.
+//  * optional_vec - reads into an Option<Vec> without a length prefix, continuing if no TLV is
+//                   present. Writes from a Vec directly, only if any elements are present. Note
+//                   that the struct deserialization macros return a Vec, not an Option.
+//  * upgradable_option - reads via MaybeReadable.
+//  * upgradable_required - reads via MaybeReadable, requiring a TLV be present but may return None
+//                          if MaybeReadable::read() returns None.
+
 /// Implements serialization for a single TLV record.
 /// This is exported for use by other exported macros, do not use directly.
 #[doc(hidden)]
@@ -29,7 +44,7 @@ macro_rules! _encode_tlv {
 		BigSize($field.serialized_length() as u64).write($stream)?;
 		$field.write($stream)?;
 	};
-	($stream: expr, $type: expr, $field: expr, vec_type) => {
+	($stream: expr, $type: expr, $field: expr, required_vec) => {
 		$crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
 	};
 	($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
@@ -41,7 +56,7 @@ macro_rules! _encode_tlv {
 	};
 	($stream: expr, $type: expr, $field: expr, optional_vec) => {
 		if !$field.is_empty() {
-			$crate::_encode_tlv!($stream, $type, $field, vec_type);
+			$crate::_encode_tlv!($stream, $type, $field, required_vec);
 		}
 	};
 	($stream: expr, $type: expr, $field: expr, upgradable_required) => {
@@ -159,7 +174,7 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
 		BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
 		$len.0 += field_len;
 	};
-	($len: expr, $type: expr, $field: expr, vec_type) => {
+	($len: expr, $type: expr, $field: expr, required_vec) => {
 		$crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
 	};
 	($len: expr, $optional_type: expr, $optional_field: expr, option) => {
@@ -172,7 +187,7 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
 	};
 	($len: expr, $type: expr, $field: expr, optional_vec) => {
 		if !$field.is_empty() {
-			$crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, vec_type);
+			$crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
 		}
 	};
 	($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
@@ -236,8 +251,8 @@ macro_rules! _check_decoded_tlv_order {
 	($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
 		// no-op
 	}};
-	($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, vec_type) => {{
-		// no-op
+	($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
+		$crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
 	}};
 	($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
 		// no-op
@@ -281,8 +296,8 @@ macro_rules! _check_missing_tlv {
 	($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 		$crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 	}};
-	($last_seen_type: expr, $type: expr, $field: ident, vec_type) => {{
-		// no-op
+	($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
+		$crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
 	}};
 	($last_seen_type: expr, $type: expr, $field: ident, option) => {{
 		// no-op
@@ -320,15 +335,16 @@ macro_rules! _decode_tlv {
 	($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
 		$field = $trait::read(&mut $reader $(, $read_arg)*)?;
 	}};
-	($reader: expr, $field: ident, vec_type) => {{
+	($reader: expr, $field: ident, required_vec) => {{
 		let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
-		$field = Some(f.0);
+		$field = f.0;
 	}};
 	($reader: expr, $field: ident, option) => {{
 		$field = Some($crate::util::ser::Readable::read(&mut $reader)?);
 	}};
 	($reader: expr, $field: ident, optional_vec) => {{
-		$crate::_decode_tlv!($reader, $field, vec_type);
+		let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
+		$field = Some(f.0);
 	}};
 	// `upgradable_required` indicates we're reading a required TLV that may have been upgraded
 	// without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
@@ -694,8 +710,8 @@ macro_rules! _init_tlv_based_struct_field {
 	($field: ident, required) => {
 		$field.0.unwrap()
 	};
-	($field: ident, vec_type) => {
-		$field.unwrap()
+	($field: ident, required_vec) => {
+		$field
 	};
 	($field: ident, optional_vec) => {
 		$field.unwrap()
@@ -720,8 +736,8 @@ macro_rules! _init_tlv_field_var {
 	($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
 		$crate::_init_tlv_field_var!($field, required);
 	};
-	($field: ident, vec_type) => {
-		let mut $field = Some(Vec::new());
+	($field: ident, required_vec) => {
+		let mut $field = Vec::new();
 	};
 	($field: ident, option) => {
 		let mut $field = None;