Some things in the LoVoN project have changed. Although the project stays open-source, it now is a project owned by NiiP. The LoVoN image is free for you to download on the bitbucket page. It can use very specific sender and receiver rules, but those are not part of the image. If you need specific filters, you'll have to contact us. (like: email white lists, user list to the system).
You can find all about the why and the how on the LoVoN project wiki page. The things that have changed the most are: image for Rasp Pi model 2, auto-start on boot, installed location = /usr/local/lovon, usage of service scripts and you can attach HDMI after boot.
Once you have put the image on an SD-card, booted, added your modem and have configured LoVoN, you can start using your Raspberry Pi model 2 as an SMS-Gateway-Server.