Morover, iocage jail util supports only FreeBSD RELEASES
I’m using the fork of original iocage called iocell. From man iocell:
create [-e] [base=[RELEASE|NAME]] [property=value] [property=value] [count=value] By default create will deploy a new jail based on the host operating systems release. This can be changed by specifying the base option. By default a basejail is created that has a common shared base. The -e switch will create an empty jail which can be used for unsupported or custom jails.