diff --git a/lightning/src/ln/outbound_payment.rs b/lightning/src/ln/outbound_payment.rs
index fb6621861cb..bbb350ffce1 100644
--- a/lightning/src/ln/outbound_payment.rs
+++ b/lightning/src/ln/outbound_payment.rs
@@ -2009,17 +2009,23 @@ impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
 		(1, reason, option),
 		(2, payment_hash, required),
 	},
+	// Added in 0.0.123. Prior versions will drop these outbounds on downgrade, which is safe because
+	// no HTLCs are in-flight.
 	(5, AwaitingInvoice) => {
 		(0, expiration, required),
 		(1, invoice_request, option),
 		(2, retry_strategy, required),
 		(4, max_total_routing_fee_msat, option),
 	},
+	// Added in 0.0.123. Prior versions will drop these outbounds on downgrade, which is safe because
+	// no HTLCs are in-flight.
 	(7, InvoiceReceived) => {
 		(0, payment_hash, required),
 		(2, retry_strategy, required),
 		(4, max_total_routing_fee_msat, option),
 	},
+	// Added in 0.0.124. Prior versions will drop these outbounds on downgrade, which is safe because
+	// no HTLCs are in-flight.
 	(9, StaticInvoiceReceived) => {
 		(0, payment_hash, required),
 		(2, keysend_preimage, required),