Cryptographic Security Platform 1.2.1 fixes the following PKI Hub 1.3.0. known issue. 

Installations with Certificate Authority do not support upgrading (EDM-19202)

PKI Hub 1.2.0 installations with the Certificate Authority deployed solution do not support upgrading to PKI Hub 1.3.0.

Workaround: Skip the 1.2.0 release and upgrade PKI Hub 1.2.0 to 1.2.1.