The extended version of IPM in the Blue Book was given content-type 22 (for P2 version 2) and is often referred to informally as P22, although that term is not used in the standards.
Rozšířená verze IPM v Blue Book dostala content-type 22 (jako P2 verze 2) a je často označována jako P22, přestože tento termín není definován v žádném standardu.