I can upgrade my Raspberry with Raspberry Pi 2 or 3?

I have a Raspberry Pi since 3 years by your datacenter. Your services are very good and will be happy to renew the subscription for the next period of 12 monts. So, I am interested whether I can upgrade my Raspberry with Raspberry Pi 2? Have I to buy another one, or I can pay the excess for the new one?
Is there any option to upgrade with the new version of Pi?

Where can I find actual haproxy and keepalived deb packages for Raspberry Pi and how I install high availability?

At https://packages.raspberry-hosting.com/ we have provided for download the latest version of the HAProxy for Raspberry Pi. There is also a init script. Packages will be updated regularly.

Raspberry HAProxy

What you need:

4x Raspberry Pi
5x IP address (1 IP is need for Virtual Interface - VIF)