It has been unofficially deprecated on the wiki for many years:
https://wiki.qemu.org/Features/QED

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 docs/about/deprecated.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 0891bbc44de..ab83626af0b 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -526,3 +526,16 @@ If the user requests a modern x86 CPU model (i.e. not one of ``486``,
 ``athlon``, ``kvm32``, ``pentium``, ``pentium2``, ``pentium3``or ``qemu32``)
 a warning will be displayed until a future QEMU version when such CPUs will
 be rejected.
+
+Block drivers
+-------------
+
+QED (since 12.0)
+''''''''''''''''
+
+The QED disk image format is not actively maintained and qcow2 has exceeded its
+features and performance for many years. Since QED was never widely deployed,
+the format is not required for compatibility reasons. It is unlikely that
+qemu-img users still need to convert images to or from QED.
+
+Use qcow2 instead of QED.
-- 
2.56.0