- you need to check that there are php-fpm patches for the specific PHP
version that you intend to use;
- you need to hand recompile PHP to use it,
- you need to hand customize the paths of the recompiled code
- you must comply with the awkward php-fpm license (non free/non OSI?)
And each time a new security/bug-fix release of PHP is out, you need to
start it all over again.
We still do prefer the Ubuntu "LESS IS MORE" way of doing things:
sudo aptitude update
sudo aptitude safe-upgrade
...and it is done!
After a few days of tests in the sandbox servers and after checking that
all is well, it is a simple matter of doing the same in the production