2.5.1 testing: [pqc] gpg exporting a secret dual key is not yet supported

[Dongsheng Song]

Hi,

After I added a ky1024_cv448 subkey, all looks good to me, but when I
export the secret key:

# gpg -K --with-keygrip --with-subkey-fingerprint --keyid-format long
/tmp/tmp.KVsqNYaBtX/pubring.kbx
-------------------------------
sec   ed448/A6FEFF804A85AF6F 2024-09-30 [C] [expires: 2025-09-30]
      A6FEFF804A85AF6F9241A47BE7FC1DEBE44C68D1B7DB99466FF00D9759B80C8A
      Keygrip = 59D1D2E1A828B4BE416A55F3ED8A38AA25D7EAF2
uid                 [ultimate] X448 User <x448 at example.com>
ssb   ed448/84F04745A03D31A7 2024-09-30 [S] [expires: 2025-09-30]
      84F04745A03D31A74EEE263ABA07623C9B501CDCF29CB787E65ACD4EC9811A95
      Keygrip = 111A1F8C33C22BE95AB6145E64B933E33C5A51BE
ssb   ky1024_cv448/A06F5C46DF43CC21 2024-09-30 [E] [expires: 2025-09-30]
      A06F5C46DF43CC21772891CFE6A228D871C2179E402F89B26555E01EA6BF5207
      Keygrip = 70DB35055368072FAE628462E555CF64909E2EBC,
                09B0D40857A3032BACDB72C55F3C19070C84858F
ssb   ed448/AA2A723E4C0C2B69 2024-09-30 [A] [expires: 2025-09-30]
      AA2A723E4C0C2B6986DE7F4C536FAE2EA6D80DEDA12DCAC5225FC3A999DB1A33
      Keygrip = 2860BFDC0E3B6E45533EE7B04CBBAEF6D7ABEE1C

# gpg --export-secret-keys --batch --passphrase="${PP}"
--pinentry-mode loopback ${fpr} > ${fpr}-k3.gpg
gpg: exporting a secret dual key is not yet supported

So what is the current backup and recovery solution for 1024_cv448
subkey? When or which version will support exporting 1024_cv448
subkey?

Thanks,
Dongsheng