any good instructions on how to upgrade php 5 to php current

Hi
my setup is on a vps

i-MSCP 1.2.0
Build: 20141230
Codename: Andromeda

vritual
Debian 8.1 jessie
50gig hd
2gig memory

are there any good instructions on how to upgrade php 5 to php current
then how to upgrade my current i-mscp to 1.2.11 without breakage if possible ?

everything is running perfect except "own cloud" it keeps showing that my php 5 is no longer
supported and that i should upgrade (own cloud is another software from I-MSCP)

thanks
barry