How to update Redmine from default debian 8 repository

Hello,
I'm new with redmine, I installed redmine from default sources in debian 8 about 2 mounths ago. All ok except of default version in debian 8 is redmine 2.5.2 version.

I'd like to update my actual version if posible from debian repositories, but I'm not sure the proccess I need to do for update to a newer version without the need of compile redmine.

Thanks and regards.