Consolidating multiple servers

Hi there,

i have got multiple servers which i have to consolidate on one. Unfortunately this means, that several websites run on fcgi others on mod_php. I tried to get the latter ones on a new server, running fcgi, but that will break the websites. I also need to use a more current OS, so i wanted to use Ubuntu 16.04, with php 7.

Any best practice to be able to do this smoothly?

Thanks and best