From 6366f8ebcbab1bc5e59325bf8a00ed96065bd671 Mon Sep 17 00:00:00 2001
From: Sjors Provoost <sjors@sprovoost.nl>
Date: Wed, 12 Jan 2022 16:37:01 +0100
Subject: bip174: document PSBT 0 handling of type > 0xFD

---
 bip-0174.mediawiki | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'bip-0174.mediawiki')

diff --git a/bip-0174.mediawiki b/bip-0174.mediawiki
index 8ef525c..874af14 100644
--- a/bip-0174.mediawiki
+++ b/bip-0174.mediawiki
@@ -819,6 +819,9 @@ If an updater is updating a PSBT and needs to add a field that is only available
 New fields should first be proposed on the bitcoin-dev mailing list.
 If a field requires significant description as to its usage, it should be accompanied by a separate BIP.
 The field must be added to the field listing tables in the Specification section.
+Although some PSBT version 0 implementations encode types as uint8_t rather than compact size,
+it is still safe to add >0xFD fields to PSBT 0, because these old parsers ignore
+unknown fields, and <keytype> is prefixed by its length. 
 
 ===Procedure For New Versions===
 
-- 
cgit v1.2.3

