how to upgrade asterisk ?

Hello,
I am using vicidialnow1.1 which have asterisk version 1.2.27.
I want to upgrade asterisk to 1.2.30.
What step I needed for this?
Thank for any help.
I am using vicidialnow1.1 which have asterisk version 1.2.27.
I want to upgrade asterisk to 1.2.30.
What step I needed for this?
Thank for any help.