Section 11.1 contains the sentence:
In a key that has a main key and subkeys, the primary key MUST be a
key capable of certification.
Suggest to change this to:
In a V4 key, the primary key MUST be a key capable of certification.
Rationale:
Frankly, because a while back, I read this as saying that if you have
a V4 key without subkeys, then the key isn't necessarily required to
be able to certify (and could thus be encrypt-only). Pretty much
everyone else read the same thing as saying that the primary key must
be capable of certification no matter what. Saying "V4" here instead
of "key that has a main key and subkeys" cannot be misunderstood.
David