From 4e9f1c0ffde6808b7ee60fd5bbc4b2a622b987a3 Mon Sep 17 00:00:00 2001
From: Heiko Schaefer <heiko@schaefer.name>
Date: Thu, 23 Nov 2023 13:19:28 +0100
Subject: [PATCH] add note to "differences between versions" chapter

---
 book/source/17-versions.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/book/source/17-versions.md b/book/source/17-versions.md
index b5ac53e..1043db1 100644
--- a/book/source/17-versions.md
+++ b/book/source/17-versions.md
@@ -5,3 +5,10 @@ SPDX-License-Identifier: CC-BY-SA-4.0
 
 (versions)=
 # Differences between OpenPGP versions
+
+```{admonition} TODO
+:class: warning
+
+write about the delta between v4 and v6, most of all
+- a starting point? https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-12.html#name-upgrade-guidance-adapting-i
+```