PHP update

[MichalE7]

Hi,
I deployed Cacti few month ago.

Operating System: Windows Server 2008 R2
Webserver: IIS 7
Cacti: 0.8.8b
Spine: n/a
MySQL: 5.6
PHP: 5.3.28
RRDTool (Cygwin or Win32 build): RRDTool 1.2.x
Net-SNMP: 5.5.1

It is running very well and I can't imagine supporting the network without it but recently security team detected that this PHP version that I'm using is vulnerable and should be patched.
My questions are:
1. Can I update just PHP without reinstalling anything else? Are there any compatibility issues?
Or should I uninstall all and do a fresh install?
2. After 5.3.x version of PHP they stopped releasing .msi version of it. As far as my research tell me, to install new version PHP I should just unzip the archive and modify PHP configuration files. As I'm a noob in this matter. Is there any instruction how to configure PHP for IIS and cacti (which files to modify)?

I would be grateful for any advice as I should progress this soon.

[BSOD2600]

Yes, the latest versions of mysql and php work with Cacti (the http://forums.cacti.net/viewtopic.php?f=3&t=14946 uses them).
Yes, you should be able to download the NTS php zip file and overwrite the existing files (assuming FastCGI, IIS, etc were all previously properly configured).
Yes, the installation guide (http://docs.cacti.net/manual:088:1_inst ... er_windows) needs to get updated.