I am currently upgrading to PR1.3 using fapman (Fast Application Manager), because even changing /etc/apt/sources.d to 1.3, "apt-get update; apt-get upgrade" did not work. In fact, I wasn't able to change extra repository to 1.3 using the standard hildon app manager (even starting as root).

Fapman, instead, worked flawless (some 1000+ packages in something like 87+ Mbytes downloading now).