DSA/ElGamal key not usable by PGP v7 (imports but won't encrypt)

[Steve Butler]

My apologies if this has a documented solution.  I pulled down this entire
archive and found some notes but not enough for me to figure out a solution.

We generated a new DSA/ElGamal key (2048 bits).  One group that is
attempting to encrypt data to send to us is unable to use the new public
key.  They have PGP v7.  It attempts to encrypt but then blows up.  Their
PGP support claims they don't support interaction with OpenPG.

I've seen the notes about Type 16 versus Type 20 ElGamal.  However, I'm
unable to determine which type we have and how to change it to the other
type (without invalidating our public keys for all the other folks).

pub  1024D
sub  2048g

and

sec  1024D
ssb  2048g

--Steve Butler

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