Smartcard working completely with GPG2 and incompletely with GPG1.4

[NIIBE Yutaka]

Hello,

Thank you for your report in detail.

chris.p.16 at gmx.de wrote:
> The commands gpg --card-status and gpg2 --card-status seem to display
> mainly the same things, the only strange line is "Key Attributes" at
> GPG 1.4:

gpg 1.4 can use gpg-agent by the option use-agent.  I think that you
enable this option in .gnupg/gpg.conf.

Yes, gpg 1.4 can be used with the gpg-agent of GnuPG 2.0, this usage is
supported well.

scdaemon in GnuPG 2.1 has been enhanced to support ECC, and the particular
protocol of KEY-ATTR has been changed.  This is the cause of the issue.

While I'm sure scdaemon 2.1 doesn't work well with gpg 1.4 by protocol
incompatibility, I'm not sure how gpg 1.4 can be used with the gpg-agent
of 2.1, in general.  In my opinion, I don't think this usage is
well supported in the current development of GnuPG.

Let us see.

Are there any reason why the combination of gpg 1.4 and gpg-agent 2.1 is
useful?
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