From 3ba7b5f2462b44a8802f09f6b51aef58a2566db1 Mon Sep 17 00:00:00 2001
From: Daira Hopwood <daira@jacaranda.org>
Date: Tue, 11 Jan 2022 13:06:51 +0000
Subject: [PATCH] ZIP 243: clarify in "Backward compatibility" that the reason
 why the ZIP 243 sighash algorithm is used for all transactions from Sapling
 activation, is that v3 transactions are no longer valid.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
---
 zip-0243.html | 2 +-
 zip-0243.rst  | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/zip-0243.html b/zip-0243.html
index 4b50f2b6..38adbe5b 100644
--- a/zip-0243.html
+++ b/zip-0243.html
@@ -437,7 +437,7 @@ vJoinSplit:      00</pre>
             <p>This proposal is deployed with the Sapling network upgrade. <a id="id14" class="footnote_reference" href="#zip-0205">6</a></p>
         </section>
         <section id="backward-compatibility"><h2><span class="section-heading">Backward compatibility</span><span class="section-anchor"> <a rel="bookmark" href="#backward-compatibility"><img width="24" height="24" src="assets/images/section-anchor.png" alt=""></a></span></h2>
-            <p>This proposal is backwards-compatible with old UTXOs. It is <strong>not</strong> backwards-compatible with older software. All transactions will be required to use this transaction digest algorithm for signatures, and so transactions created by older software will be rejected by the network.</p>
+            <p>This proposal is backwards-compatible with old UTXOs. It is <strong>not</strong> backwards-compatible with older software. Given that v3 transaction formats will be invalid from the Sapling upgrade, all transactions will be required to use this transaction digest algorithm for signatures, and so transactions created by older software will be rejected by the network.</p>
         </section>
         <section id="reference-implementation"><h2><span class="section-heading">Reference Implementation</span><span class="section-anchor"> <a rel="bookmark" href="#reference-implementation"><img width="24" height="24" src="assets/images/section-anchor.png" alt=""></a></span></h2>
             <p><a href="https://github.com/zcash/zcash/pull/3233">https://github.com/zcash/zcash/pull/3233</a></p>
diff --git a/zip-0243.rst b/zip-0243.rst
index 25770ad7..4c8c5c0a 100644
--- a/zip-0243.rst
+++ b/zip-0243.rst
@@ -513,8 +513,9 @@ Backward compatibility
 ======================
 
 This proposal is backwards-compatible with old UTXOs. It is **not** backwards-compatible with older software.
-All transactions will be required to use this transaction digest algorithm for signatures, and so transactions
-created by older software will be rejected by the network.
+Given that v3 transaction formats will be invalid from the Sapling upgrade, all transactions will be required
+to use this transaction digest algorithm for signatures, and so transactions created by older software will
+be rejected by the network.
 
 
 Reference Implementation