php4 to php5 on ispconfig server

[provell]

Hi all,

I have setup a ispconfig/debian sarge server at the time with the perfect setup.
Later I have upgraded debian sarge to etch but my php version was still 4.
Currently etch has php5 packages but are not upgradet automaticaly.

Before I upgrade from etch to lenny I would like to upgrade php4 to php5.

Is that a smart thing to do and what would be the best way to do it.
Would a "apt-get install php5" be enough?

Will it affect anything regarding to ispconfig as it uses it's own php5 compilation?

Thanks in advance.

Rgds Edo