Upgrading a few essential packages ..

[Anurag Jalan <a_jalan vsnl com>]

Hi all,

For the first time since I installed Linux in June,
I need to upgrade some of my packages . 

I have MySQL 3.22.32 , PHP3.0.16 statically linked to Apache 1.3.12
I need to upgrade to MySQL  3.23 , PHP 4.02 and maybe recompile Apache with
DSO support and SSL . 

I've never upgraded packages before .. a few questions..

Do I point the --prefix= to the old paths eg /usr/local/apache & 
/usr/local/mysql ? Would the new compile rewrite over the older binaries ?
What precautions should I take so as not to lose my working setup ?
Wouldn't I have to reconfigure httpd.conf from scratch ( i have 2
name-based virtual hosts and 
a few protected folders ) .

Further, is there anything to be gained in installing *both* PHP3 & PHP4
... If I install just PHP4 would it recognize the .php3 extension ? Would
the old scripts still work ?

Finally, My programmers want me to install a Java environment for a Chat
program we plan to develop for use on our site ? Is there a good PHP based
solution to this ? How do Servlets & JSP compare with PHP , performance wise ?

Thanks in advance

Anurag